SQL: Add hint to error message when user hits a limit

[chaas]

When users hit limits due to system vars, such as max_tables, add a hint for how to get unblocked. E.g.

ERROR: creating table would violate max_tables limit (desired: 26, limit: 25, current: 25)

For limits controlled by Materialize (not configurable by the organization admin, only configurable via LaunchDarkly): Hint should tell user: to change the limit, contact support.

For limits controlled by the org (thus configurable by an admin): Hint should tell user: to set the system variable to another value, contact an organization admin to run ALTER SYSTEM SET.

In both cases, we should consider linking to the docs https://materialize.com/docs/sql/alter-system-set/#system-variables. That docs link has the list of limits and which ones are controlled by an admin vs Materialize.

For local development, this will be misleading b/c the user can run ALTER SYTEM SET on all system vars.