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.
