[EPIC] Feat: Add a hosted version that covers non-HA users

[Pascal-ZeGerman]

• [SPIKE] Explore structure to also cover a hosted version
• As a user, I want to be able to use the feature even I am not using HA
• As a user, I want to be able to enter GPS data either my car's login
• As a user, I want to be sure that the data privacy of my data is ensured. Hoster can never have access to GPS coordinates even for bug tracking, data should only be stored for minimal amount of time, data spill between two accounts should be prevented.
• [SPIKE] As a user, I want to also use automated location savings (Apple Maps When disconnecting CarPlay) if I don't want to connect my car's app to this service
• As a user, I want to also get calendar notifications (CalDav, but also an .ics feed subscription or similar) as easily as possible
• As a maintainer, I want to minimize double work by sharing core logic and core assets between the HA and non-HA version