Rework database wrapper

[DrMurx]

The current database access is a historically grown monster structure. It lacks separation of concerns, is a mix of data provider, mapper/converter and other parts of the business logic that don't belong here.

Dropping monocle support opened the door for some refactoring. This would include the following steps:

• Merge dbWrapperBase and rmWrapper into a single, humongous DbWrapper to ease up the further steps.
• Break DbWrapper into smaller "data providers" for the different parts of the application (MITM, Route planning, Webhook, Map/Madmin).
• Extract high-level services, business logic and data converters from the data providers so they remain a low level data access layer.
• Group data access layer per table (as preparation for some kind of ORM in the future).

This is a meta issue to track and discuss the progress.

[sn0opy]

Related/affected: #539

[DrMurx]

Related/affected: #539

Related, but luckily almost not affected. The API for the MAD config already uses some kind of dedicated unified data provider.

[Expl0dingBanana]

These changes have been merged into #539, f620b6c

[DrMurx]

@Expl0dingBanana Only the first patch ;) more to come.

[Expl0dingBanana]

@DrMurx Do you still need this enhancement open?

[DrMurx]

@Expl0dingBanana Absolutely. I'll go forward with that as soon as my spare time allows.