Adds support for new downsampling UX

[Harkishen-Singh]

Signed-off-by: Harkishen-Singh harkishensingh@hotmail.com

This commit updates the UX for creating downsampled data for Prometheus metrics.

Now, downsampling can be done by

metrics:
  downsampling:
  - interval: 5m
    retention: 30d
  - interval: 1h
    retention: 365d

The above dataset-config setting will create 2 downsampling, ds_5m (interval 5m & retention 30d) and ds_1h (interval 1h & retention 365d).

If an entry is removed, like

metrics:
  downsampling:
  - interval: 1h
    retention: 365d

Then we disable the ds_5m downsampling from refreshing. Deletion can only happen via SQL, CALL _prom_catalog.delete_downsampling(<schema_name>). This keeps the UX clean and simple.

If the removed downsampling is applied again later on, we simply enable the refreshing.

This also means that this commit adds ability to enable or disable downsampling as well.

Description

Merge requirements

Please take into account the following non-code changes that you may need to make with your PR:

• [ ] CHANGELOG entry for user-facing changes
• [ ] Updated the relevant documentation

[Harkishen-Singh]

Note for reviewers: The lint tests fails at the moment. I haven't fixed them since I aim to first be sure that we are fine with the new way day.Duration is implemented. Once we are fine, I will fix the linting tests. Otherwise, if we plan to change day.Duration down the line, it will consume good time updating the tests.

[Harkishen-Singh]

Note: Commit Adds support to query default downsampling views in absence of __column__ is not directly related to this PR, but it was more comfortable and faster for me to include in this PR, than wait for approval and merge and then open a following PR.

[Harkishen-Singh]

This (_prom_catalog.create_or_update_downsampling) might be helpful while reviewing.

[niksajakovljevic]

Note: Commit Adds support to query default downsampling views in absence of column is not directly related to this PR, but it was more comfortable and faster for me to include in this PR, than wait for approval and merge and then open a following PR.

Btw it does seem that commit is gone so can't really follow through that part