feat: add information_schema.key_column_usage

[dimbtp]

I hereby agree to the terms of the GreptimeDB CLA

What's changed and what's your intention?

• add information_schema.key_column_usage table

Checklist

• I have written the necessary rustdoc comments.
• I have added the necessary unit tests and integration tests.
• This PR does not require documentation updates.

Refer to a related PR or issue link (optional)

#2931

[codecov]

Codecov Report

Attention: 168 lines in your changes are missing coverage. Please review.

Comparison is base (6070e88) 85.45% compared to head (ed504bc) 84.81%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3057      +/-   ##
==========================================
- Coverage   85.45%   84.81%   -0.65%     
==========================================
  Files         799      800       +1     
  Lines      129155   129395     +240     
==========================================
- Hits       110373   109740     -633     
- Misses      18782    19655     +873     

[killme2008]

Great job! Thank you.

A few suggestions are attached, please take a look. And i think it's better to add some sql to test this table to tests/cases/standalone/common/system/information_schema.sql, just like

greptimedb/tests/cases/standalone/common/system/information_schema.sql

Line 69 in 6070e88

select * from CHARACTER_SETS;

We can ensure the virutal table results are correct.

[killme2008]

BTW. After #3054 merged, some conflicts have to be resolved right now.

[killme2008]

LGTM. Thank you very much!