GODT-1667: bridge-gui spawns bridge process. [skip-ci]

Other: renaming of bridge-gui.
WIP: locate bridge exe.
WIP: bridge process launch.
WIP: cleaner closure of bridge.
WIP: grpcClient connection retries.
WIP: clean exit when bridge process is killed.

Fixed issues from MR review. [skip-ci].

WIP: Fixed gRPC case in CMakelists.txt [skip-ci]

It caused issues on Debian.

WIP: update gRPC/protobuf and tweaked CMakeLists.txt. [skip-ci]

WIP: Fixed a bug where splash screen could not be dismissed. [skip-ci]

internal/frontend/bridge-gui/qml/Notifications/Notification.qml

@@ -0,0 +1,54 @@
+// Copyright (c) 2022 Proton AG
+//
+// This file is part of Proton Mail Bridge.
+//
+// Proton Mail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Proton Mail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Proton Mail Bridge. If not, see <https://www.gnu.org/licenses/>.
+
+import QtQml 2.12
+import QtQuick.Controls 2.12
+
+QtObject {
+    id: root
+
+    default property var children
+
+    enum NotificationType {
+        Info = 0,
+        Success = 1,
+        Warning = 2,
+        Danger = 3
+    }
+
+    // title is used in dialogs only
+    property string title
+    // description is used in banners and in dialogs as description
+    property string description
+    // brief is used in status view only
+    property string brief
+
+    property string icon
+    property list<Action> action
+    property int type
+    property int group
+
+    property bool dismissed: false
+    property bool active: false
+    readonly property var occurred: active ? new Date() : undefined
+
+    property var data
+
+    onActiveChanged: {
+        dismissed = false
+    }
+}

internal/frontend/bridge-gui/qml/Notifications/NotificationFilter.qml

@@ -0,0 +1,114 @@
+// Copyright (c) 2022 Proton AG
+//
+// This file is part of Proton Mail Bridge.
+//
+// Proton Mail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Proton Mail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Proton Mail Bridge. If not, see <https://www.gnu.org/licenses/>.
+
+import QtQml 2.12
+import QtQml.Models 2.12
+
+// contains notifications that satisfy black- and whitelist and are sorted in time-occurred order
+ListModel {
+    id: root
+
+    enum FilterConsts {
+        None = 0,
+        All = 255
+    }
+
+    property int whitelist: NotificationFilter.FilterConsts.All
+    property int blacklist: NotificationFilter.FilterConsts.None
+
+    property Notification topmost
+    property var source
+
+    property bool componentCompleted: false
+    Component.onCompleted: {
+        root.componentCompleted = true
+        root.rebuildList()
+    }
+
+    // overriding get method to ignore any role and return directly object itself
+    function get(row) {
+        if (row < 0 || row >= count) {
+            return undefined
+        }
+        return data(index(row, 0), Qt.DisplayRole)
+    }
+
+    function rebuildList() {
+        // avoid evaluation of the list before Component.onCompleted
+        if (!root.componentCompleted) {
+            return
+        }
+
+        for (var i = 0; i < root.count; i++) {
+            root.get(i).onActiveChanged.disconnect( root.updateList )
+        }
+
+        root.clear()
+
+        if (!root.source) {
+            return
+        }
+
+        for (i = 0; i < root.source.length; i++) {
+            var obj = root.source[i]
+            if (obj.group & root.blacklist) {
+                continue
+            }
+
+            if (!(obj.group & root.whitelist)) {
+                continue
+            }
+
+            root.append({obj})
+            obj.onActiveChanged.connect( root.updateList )
+        }
+    }
+
+    function updateList() {
+        var topmost = null
+
+        for (var i = 0; i < root.count; i++) {
+            var obj = root.get(i)
+
+            if (!obj.active) {
+                continue
+            }
+
+            if (topmost && (topmost.type > obj.type)) {
+                continue
+            }
+
+            if (topmost && (topmost.type === obj.type) && (topmost.occurred > obj.occurred)) {
+                continue
+            }
+
+            topmost = obj
+        }
+
+        root.topmost = topmost
+    }
+
+    onWhitelistChanged: {
+        root.rebuildList()
+    }
+    onBlacklistChanged: {
+        root.rebuildList()
+    }
+    onSourceChanged: {
+        root.rebuildList()
+    }
+}

internal/frontend/bridge-gui/qml/Notifications/qmldir

@@ -0,0 +1,6 @@
+module Notifications
+depends QtQml 2.12
+
+Notifications 1.0 Notifications.qml
+NotificationFilter 1.0 NotificationFilter.qml
+Notification 1.0 Notification.qml