Remove need for rxdb-internal-types.ts

[marceljuenemann]

rxdb-internal-types.ts currently contains some types copied from RxDB. Two options:

1. Ask RxDB to add those types to their exports
2. Don't reference those types at all and just copy the fields into SupabaseReplicationOptions. This might actually be good for readability, and we are already documenting all options in the README anyways. The only downside is that if RxDB adds a new option, it won't automatically become part of our API, but rather will need to be added explicitly. Although arguably, that might also not be the worst anyways in order to make sure any option is actually supported by us (e.g. waitForLeadership is not supported)

[marceljuenemann]

Filed RxDB issue here: pubkey/rxdb#4606