* [FEAT] improve update_admin_settings
while working on the push notification pr i found it very hard just to update
2 settings inside the db, so i improved upon update_admin_settings.
now you just need to provide a dict with key/values you want to update inside db.
also debugging the endpoints for update_settings i found despite the type of `EditableSettings`
fastapi did in fact pass a dict.
* t
* use `EditableSettings` as param in update_settings
* fix settings model validation
we previously overrode the pydantic validation with our own method
* make `LnbitsSettings` a `BaseModel` and only add `BaseSettings` later
this allows us to instantiate `EditableSettings` without the environment values being loaded in
* add test
* forbid extra fields in update api
* fixup
* add test
* test datadir
* move UpdateSettings
* fix compat
* fixup webpush
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Co-authored-by: jacksn <jkranawetter05@gmail.com>
