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/build.sh

@@ -0,0 +1,22 @@
+# 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/>.
+
+
+#!/bin/bash
+BUILD_DIR="./cmake-build-debug"
+cmake  -DCMAKE_BUILD_TYPE=Debug -G Ninja -S . -B ${BUILD_DIR}
+ninja -C ${BUILD_DIR}