sql: support WITH ADMIN OPTION when granting roles

[rafiss]

As described in the Postgres docs: https://www.postgresql.org/docs/current/sql-grant.html

If WITH ADMIN OPTION is specified, the member can in turn grant membership in the role to others, and revoke membership in the role as well. Without the admin option, ordinary users cannot do that. A role is not considered to hold WITH ADMIN OPTION on itself, but it may grant or revoke membership in itself from a database session where the session user matches the role. Database superusers can grant or revoke membership in any role to anyone. Roles having CREATEROLE privilege can grant or revoke membership in any role that is not a superuser.

Unlike the case with privileges, membership in a role cannot be granted to PUBLIC. Note also that this form of the command does not allow the noise word GROUP.

This is analogous to WITH GRANT OPTION: #67410

Epic CRDB-2587

[rafiss]

this is supported already; i missed it