Refactor code for getting time bucket function Oid

[fabriziomello]

This is a small refactoring for getting time bucket function Oid from a view definition. It will be necessary for a following PRs for completely remove the uncessary catalog metadata table continuous_aggs_bucket_function.

Also added a new SQL function cagg_get_bucket_function_info to return all time_bucket information based on a user view definition.

Disable-check: force-changelog-file

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 81.62162% with 34 lines in your changes missing coverage. Please review.

Project coverage is 81.76%. Comparing base (59f50f2) to head (aab6d93). Report is 229 commits behind head on main.

Files	Patch %	Lines
tsl/src/continuous_aggs/utils.c	78.48%	2 Missing and 15 partials :warning:
tsl/src/continuous_aggs/common.c	86.59%	0 Missing and 13 partials :warning:
src/utils.h	20.00%	1 Missing and 3 partials :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #7042 +/- ## ========================================== + Coverage 80.06% 81.76% +1.69% ========================================== Files 190 200 +10 Lines 37181 37345 +164 Branches 9450 9740 +290 ========================================== + Hits 29770 30535 +765 + Misses 2997 2891 -106 + Partials 4414 3919 -495 ```

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