* Renaming GUI, CLI, no-impact config.
* License header and documentation rebranding.
* Rename app title and vendor. Impact: manual install
* Migrating mac keychain and launch on startup.
* Fix linter and linter renaming
- pkg/pmapi: Reduce max number of retries
- test/features: tweak create mailbox scenarios.
- test/context: change order of clean up steps
- test/context: logger field
- test/context: message preparation per username
- test/context: check that eventID has changed after adding messages
- test/features: make sure we wait 15sec before detecting import duplicates
- [x] write tests to check that IMAP and SMTP servers are closed when there
is no internet
- [x] always create new go-smtp instance during listenAndServe(int)
