sql: Role management, CREATEROLE privilege

[jseldess]

PR: cockroachdb/cockroach#44232

From release notes:

Modified the CREATE ROLE statement to add the CREATEROLE option. Also added the ALTER ROLE statement and the CREATEROLE privilege. It is managed by choosing options when creating and altering a role. Example: CREATE ROLE role WITH CREATEROLE; [#44232][#44232] {% comment %}doc{% endcomment %}

[Amruta-Ranade]

Addressed in #7061