Time tracking rework and Hackatime OAuth Integration

I am currently reworking the entire way time is tracked for jus’study. Beforehand the time was tracked in the devlog database table. This now introduces a bunch of problems if you want to for example alter that data. Because of that the idea is to move to a design that I call “time ledger”. Basically any “event” like adding a devlog adds a duration (can be negative to subtract). This way it is way more extensible. Oh yeah and I made an integration for hackatime oauth. Right now I am trying to write sql-migrations so that I can migrate to the new database schema without deleting everything.