JdbcOAuth2AuthorizationService should not use Blob

[clgraf]

JdbcOAuth2AuthorizationService persists the tokens as Blobs (authorization_code_value, oidc_id_token_value, refresh_token_value and authorization_code_value).

It works great with H2 but I'm not sure if it works with Postgres (my case) or even another database.
Other point, it's harder to query the database directly, for maintenence or debugging. I'm not sure about performance.

All above fields can be easily represented as Strings, so my sugestion is to change the sql types to Varchar instead of Blob.

BTW, maybe there is a good reason to use Blobs but I can't see.

[jgrandja]

@clgraf We've aligned JdbcOAuth2AuthorizationService with JdbcOAuth2AuthorizedClientService (in spring-security-oauth2-client) as they both use blob for storing token credentials.

If you want to use varchar instead, you may customize the configuration. See this comment for further details.