Remove the Identus SDK Store by default and remove all references to RXDB

[elribonazo]

Proposed feature

Improve the Typescript SDK documentation to clearly explain how to:

1. Create a custom Storage
2. Use the available community storages for Identus (RXDB and RIDB)
3. Customize the storages to use a different storage source (inMemory, indexDB, localStorage, Level)

We should provide documentation on how to build storages for FE (browser, electron) but also on nodejs backends like Level, etc and explain how to customize the storage with encryption, migrations, etc.

We should also document how people can, using the same Identus store, extend the tables (models) for their own use-cases and integrate everything into a single database connector.

Anything else?

No response