Add a dedicated go-routine whose sole responsibility is to manage the
life time of the IMAP and SMTP servers and their listeners.
The current implementation behaves the same way as the previous state.
The new behavior will be implemented in a follow MR.
WIP: updates
WIP: cache on disk and autostart.
WIP: mail, keychain and more.
WIP: updated grpc version in go mod file.
WIP: user list.
WIP: RPC service placeholder
WIP: test C++ RPC client skeleton.
Other: missing license script update.
WIP: use Qt test framework.
WIP: test for app and login calls.
WIP: test for update & cache on disk calls.
WIP: tests for mail settings calls.
WIP: all client tests.
WIP: linter fixes.
WIP: fix missing license link.
WIP: update dependency_license script for gRPC and protobuf.
WIP: removed unused file.
WIP: app & login event streaming tests.
WIP: update event stream tests.
WIP: completed event streaming tests.
GODT-1554: qt C++ frontend skeleton.
WIP: C++ backend declaration.
wip: started drafting user model.
WIP: users. not functional.
WIP: invokable methods
WIP: Exception class + backend 'injection' into QML.
WIP: switch to VCPKG to ease multi-arch compilation, C++ RPC client skeleton.
WIP: Renaming and reorganisation
WIP:introduced new 'grpc' go frontend.
WIP: Worker & Oveerseer for thread management.
WIP: added log to C++ app.
WIP: event stream architecture on Go side.
WIP: event parsing and streamer stopping.
WIP: Moved grpc to frontend subfolder + use vcpkg for gRPC and protobuf.
WIP: windows building ok
WIP: wired a few messages
WIP: more wiring.
WIP: Fixed imports after rebase on top of devel.
WIP: wired some bool and string properties.
WIP: more properties.
WIP: wired cache on disk stuff
WIP: connect event watcher.
WIP: login
WIP: fix showSplashScreen
WIP: Wired login calls.
WIP: user list.
WIP: Refactored main().
WIP: User retrieval .
WIP: no shared pointer in user model.
WIP: fixed user count.
WIP: cached goos.
WIP: Wired autostart
WIP: beta channel toggle wired.
WIP: User removal
WIP: wired theme
WIP: implemented configure apple mail.
WIP: split mode.
WIP: fixed user updates.
WIP: fixed Quit from tray icon
WIP: wired CurrentEmailClient
WIP: wired UseSSLForSMTP
WIP: wired change ports .
WIP: wired DoH. .
WIP: wired keychain calls.
WIP: wired autoupdate option.
WIP: QML Backend clean-up.
WIP: cleanup.
WIP: moved user related files in subfolder. .
WIP: User are managed using smart pointers.
WIP: cleanup.
WIP: more cleanup.
WIP: mail events forwarding
WIP: code inspection tweaks from CLion.
WIP: moved QML, cleanup, and missing copyright notices.
WIP: Backend is not QMLBackend.
Other: fixed issues reported by Leander. [skip ci]
