feat: support plugin_metadata of apisix

[AlinsRan]

Type of change:

• Bugfix
• New feature provided
• Improve performance
• Backport patches

What this PR does / why we need it:

• Proposal: Add support for APISIXPluginMetadata function #1372

Pre-submission checklist:

• Did you explain what problem does this PR solve? Or what new features have been added?
• Have you added corresponding test cases?
• Have you modified the corresponding document?
• Is this PR backward compatible? If it is not backward compatible, please discuss on the mailing list first

[codecov-commenter]

Codecov Report

Merging #1369 (1c39d4c) into master (c38ae66) will decrease coverage by 0.45%.
The diff coverage is 38.09%.

@@            Coverage Diff             @@
##           master    #1369      +/-   ##
==========================================
- Coverage   40.89%   40.43%   -0.46%     
==========================================
  Files          78       82       +4     
  Lines        7231     7436     +205     
==========================================
+ Hits         2957     3007      +50     
- Misses       3933     4081     +148     
- Partials      341      348       +7     

Impacted Files	Coverage Δ
pkg/apisix/apisix.go	61.36% <ø> (ø)
pkg/apisix/resource.go	56.79% <0.00%> (-6.23%)	⬇️
pkg/config/config.go	66.34% <ø> (ø)
...providers/k8s/configmap/translation/translation.go	0.00% <0.00%> (ø)
pkg/apisix/plugin_metadata.go	4.39% <4.39%> (ø)
pkg/apisix/nonexistentclient.go	41.20% <9.09%> (-2.07%)	⬇️
pkg/providers/utils/manifest.go	42.79% <54.16%> (-2.83%)	⬇️
pkg/providers/k8s/configmap/translation/parse.go	55.55% <55.55%> (ø)
...ers/k8s/configmap/translation/configyaml_parser.go	80.00% <80.00%> (ø)
pkg/apisix/cluster.go	38.05% <94.11%> (+3.57%)	⬆️
... and 8 more

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