GODT-22: Frontend-backend

- GODT-1246 Implement settings view.
- GODT-1257 GODT-1246: Account and Help view
- GODT-1298: Minimal working build (panics)
- GODT-1298: loading QML (needs Popup window)
- GODT-1298: WARN: Adding PopupWindow not possible!
    In therecipe qt the `quickwidgets` classes are within `quick` module, but
    forgot to add library and include paths into cgo flags. Therefore
    compilation fails and it would be hard to patch therecipe in order to
    fix it.

    I am not sure if rewrite PopupWindow into go would make any difference,
    therefore I decided to use normal QML Window without borders.
- GODT-1298: Rework status window, add backend props, slots and signals.
- GODT-1298: Users
- GODT-1298: Login
- GODT-1298: WIP Help and bug report
- GODT-1178: MacOS dock icon control
- GODT-1298: Help, bug report, update and events
- GODT-1298: Apple Mail config and Settings (without cache on disk)

internal/frontend/qt/frontend_help.go

@@ -0,0 +1,45 @@
+// Copyright (c) 2021 Proton Technologies AG
+//
+// This file is part of ProtonMail Bridge.
+//
+// ProtonMail 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.
+//
+// ProtonMail 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 ProtonMail Bridge.  If not, see <https://www.gnu.org/licenses/>.
+
+// +build build_qt
+
+package qt
+
+func (f *FrontendQt) setVersion() {
+	f.qml.SetVersion(f.programVersion)
+}
+
+func (f *FrontendQt) setLogsPath() {
+	path, err := f.locations.ProvideLogsPath()
+	if err != nil {
+		f.log.WithError(err).Error("Cannot update path folder")
+		return
+	}
+	f.qml.SetLogsPath(path)
+}
+
+func (f *FrontendQt) setLicensePath() {
+	f.qml.SetLicensePath(f.locations.GetLicenseFilePath())
+}
+
+func (f *FrontendQt) setCurrentEmailClient() {
+	f.qml.SetCurrentEmailClient(f.userAgent.String())
+}
+
+func (f *FrontendQt) reportBug(description, address, emailClient string, includeLogs bool) {
+	//TODO
+}