* More Options refactoring
Continues refactoring config classes to use the propert Options pattern where possible.
DataDirectories and DatabaseOptions are now configured the Options pattern and the BTCPayOptions is now moved alongside the other config setup
* Move COnfigure logic for Options to the Startup
This allows plugins to create custom dbcontexts, which would be namespaced in the scheme with a prefix. Migrations are supported too and the table would be prefixed too