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/Configuration.qml

@@ -0,0 +1,73 @@
+// 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 QtQuick 2.13
+import QtQuick.Layouts 1.12
+import QtQuick.Controls 2.12
+import QtQuick.Controls.impl 2.12
+
+import Proton 4.0
+
+Rectangle {
+    id: root
+
+    property ColorScheme colorScheme
+    property string title
+    property string hostname
+    property string port
+    property string username
+    property string password
+    property string security
+
+    implicitWidth: 304
+    implicitHeight: content.height + 2*root._margin
+
+    color: root.colorScheme.background_norm
+    radius: ProtonStyle.card_radius
+
+    property int _margin: 24
+
+    ColumnLayout {
+        id: content
+        width: root.width - 2*root._margin
+        anchors{
+            top: root.top
+            left: root.left
+            leftMargin   : root._margin
+            rightMargin  : root._margin
+            topMargin    : root._margin
+            bottomMargin : root._margin
+        }
+
+        spacing: 12
+
+        Label {
+            colorScheme: root.colorScheme
+            text: root.title
+            type: Label.Body_semibold
+        }
+
+        Item{}
+
+        ConfigurationItem{ colorScheme: root.colorScheme; label: qsTr("Hostname") ; value: root.hostname }
+        ConfigurationItem{ colorScheme: root.colorScheme; label: qsTr("Port")     ; value: root.port     }
+        ConfigurationItem{ colorScheme: root.colorScheme; label: qsTr("Username") ; value: root.username }
+        ConfigurationItem{ colorScheme: root.colorScheme; label: qsTr("Password") ; value: root.password }
+        ConfigurationItem{ colorScheme: root.colorScheme; label: qsTr("Security") ; value: root.security }
+    }
+}
+