[SPARK-30517][SQL] Support SHOW TABLES EXTENDED

[ajithme]

What changes were proposed in this pull request?

WIP
Added a syntax for SHOW TABLES EXTENDED which can output a additional column compared to SHOW TABLES which prints the table type with possible values MANAGED,EXTERNAL,VIEW
Also to reduce complexity, this PR breaks org.apache.spark.sql.execution.command.ShowTablesCommand which was responsible for SHOW TABLES and SHOW TABLE command into separate classes

Why are the changes needed?

Intention is to support show tables with a additional column 'type' where type can be MANAGED,EXTERNAL,VIEW using which user can query only tables of required types, like listing only views or only external tables (using a where clause over type column).

Usecase example:
Currently its not possible to list all the VIEWS, but other technologies like hive support it using SHOW VIEWS, mysql supports it using a more complex query SHOW FULL TABLES WHERE table_type = 'VIEW;

Decide to take mysql approach as it provides more flexibility for querying.

Does this PR introduce any user-facing change?

Yes. New option EXTENDED for SHOW TABLES command

How was this patch tested?

TODO:

1. Add UTs
2. where clause support
3. V2 catalog support

[ajithme]

cc @srowen @dongjoon-hyun @vanzin @HyukjinKwon @maropu @cloud-fan Please let me know your opinion about this feature proposal

[AmplabJenkins]

Can one of the admins verify this patch?

[github-actions]

We're closing this PR because it hasn't been updated in a while. This isn't a judgement on the merit of the PR in any way. It's just a way of keeping the PR queue manageable.
If you'd like to revive this PR, please reopen it and ask a committer to remove the Stale tag!