feat: support passing license as file

[arkbriar]

What's changed and what's your intention?

PLEASE DO NOT LEAVE THIS EMPTY !!!

Please explain IN DETAIL what the changes are in this PR and why they are needed:

Note

The environment variable used to pass the file path is RW_LICENSE_KEY_PATH due to a mistake in the original PR. We'll keep using it instead of changing it.

• Support passing license keys via mounted secret file, which enables automatic license updating. Upstream PR: feat(meta): watch and reload license key from file risingwave#18768
• Support version based auto detection and enablement of the feature and the ability of manual overriding.
• The PR maintains backward compatibility at the API level.

Checklist

• I have written the necessary docs and comments
• I have added necessary unit tests and integration tests

Refer to a related PR or issue link (optional)

[codecov]

Codecov Report

Attention: Patch coverage is 90.90909% with 9 lines in your changes missing coverage. Please review.

Project coverage is 55.43%. Comparing base (c76f925) to head (0d8c9c2).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
apis/risingwave/v1alpha1/zz_generated.deepcopy.go	0.00%	6 Missing ⚠️
pkg/factory/risingwave_object_factory.go	96.77%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #732      +/-   ##
==========================================
+ Coverage   55.03%   55.43%   +0.40%     
==========================================
  Files          40       40              
  Lines        6679     6757      +78     
==========================================
+ Hits         3676     3746      +70     
- Misses       2877     2884       +7     
- Partials      126      127       +1     

Flag	Coverage Δ
unittests	55.43% <90.90%> (+0.40%)	⬆️

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[fuyufjh]

LGTM!

[fuyufjh]

Hmmmm, I think it's not necessary to make this configurable. But anyway not a big deal.