[Refactor]: Get Rid of SQLAlchemy

[Computerdores]

So far we have been using SQLAlchemy extensively for the DB interactions, which has lead to a list of problems holding us back in some places:

• sqlalchemy seems to be a major performance bottleneck at this point, as the SQL queries for the search are significantly faster when executed in the sqlite cli
• foreign key clauses don't appear to be supported, meaning that we have to manually issue delete queries
• PRAGMA isn't supported either and would give us a proper place to store the DB schema version (see pragma user_version) (though this is just a nice-to-have and the disadvantage of changing the version stuff again might outweigh the benefit here)
• sqlalchemy is also just massively overkill for what we are doing, which complicates certain parts of the code

I suggest we move from using SQLAlchemy to using a plain sql for most of the DB interface and a minimal query building library like sql_fusion for the query builder

For more detail see past discussion on the discord, but I suggest we keep the important stuff regarding (specifically if we decide on anything) on Github.