Fix backup post hook issue

[ywk253100]

Fixes #8159 on main branch.

This PR introduces an overall Handler to handle all kinds of hooks.

The basic workflow is as follows:

1. The Parser parses the hooks from different specs into a common ResourceHook structure.
2. The Handler handles the ResourceHook by delegating to a specific ResourceHandler according to the hook type:
   • podBackupPreHookHandler: handles the backup pre hook for pods
   • podBackupPostHookHandler: handles the backup post hook for pods

The changes in this PR will be cherry-picked to branch 1.15 to fix #8159.

And will create another PR to cover restore init/exec hooks for pods and the PR will be only available on main (tracked by #8507 )

[kaovilai]

changelog check

Edit: nvm.. ci failed

[codecov]

Codecov Report

Attention: Patch coverage is 86.57718% with 40 lines in your changes missing coverage. Please review.

Project coverage is 59.08%. Comparing base (aa7ca15) to head (3a45a10).
Report is 5 commits behind head on main.

Files with missing lines	Patch %	Lines
internal/hook/parser.go	80.95%	17 Missing and 3 partials ⚠️
pkg/backup/backup.go	82.60%	6 Missing and 2 partials ⚠️
internal/hook/handler.go	96.34%	2 Missing and 1 partial ⚠️
internal/hook/pod_backup_post_hook_handler.go	86.36%	2 Missing and 1 partial ⚠️
internal/hook/pod_backup_pre_hook_handler.go	85.00%	2 Missing and 1 partial ⚠️
pkg/podvolume/backupper.go	75.00%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8490      +/-   ##
==========================================
+ Coverage   59.02%   59.08%   +0.06%     
==========================================
  Files         369      374       +5     
  Lines       39056    39214     +158     
==========================================
+ Hits        23052    23169     +117     
- Misses      14542    14575      +33     
- Partials     1462     1470       +8     

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[ywk253100]

Here is a limitation:
The logic here waits all PVBs of the whole backup to be completed before executing the hooks. This delays the hook execution of one pod although it isn't necessary.

The ideal behavior should be only wait the PVBs belongs to one ItemBlock to be completed before executing the hooks, but this involves the refactor for podvolume.Backupper to make is capable to check whether the PVBs of one ItemBlock completed. The effort isn't tiny, so created another issue #8506 to track.