Adds a new table, nordigen, with the access and refresh token, along
with their validity.
The Export/Import test would raise an integrety with the use of a real
DB and the export of the transaction IDs, so add a try-except block to
the database session to catch the error and re-raise an ImportError.
The `CategorySelector` was possibly added to be incremented with other
attributes. However, since none other that the selector enum is used at
the moment, it is only adding unnecessary cluter.
The category selector value is moved to the parent
`TransactionCategory`.
Each children is essentually a type of transaction. We currently have:
- bank transactions
- money transactions
- split transactions
The table inheritance is implemented as a single table, with a
polymorphic type and Null columns.
Adds a IsSplit interface, which will later be used for the category
views, so as to not repeat transactions.
Sometimes transctions are directly related to one another w/o being of
an equal value, e.g. someone pays for the meal w/ the CC, and everyone
pays him/her.
Clear leftover __repr__ methods in the model classes, the dataclass
decorator will create those automatically.
Uses the rules defined for each category to classify each transaction.
Fixes the categorize command, which was broken from previous refactors.
Swaps str type on the categories_rules date to date.
