feat: added sample for vars in Route & improve Typings

[juzhiyuan]

Please answer these questions before submitting a pull request, or your PR will get closed.

Why submit this pull request?

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

What changes will this PR take into?

According to https://github.com/apache/apisix/blob/master/apisix/schema_def.lua#L335

• added Methods for http_methods;
• added i18n for Advaned Route Match
• ...

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

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[codecov-io]

Codecov Report

Merging #1771 (1927e13) into master (7f041df) will increase coverage by 0.30%.
The diff coverage is 60.71%.

@@            Coverage Diff             @@
##           master    #1771      +/-   ##
==========================================
+ Coverage   72.50%   72.81%   +0.30%     
==========================================
  Files         113      119       +6     
  Lines        2695     2836     +141     
  Branches      650      681      +31     
==========================================
+ Hits         1954     2065     +111     
- Misses        741      771      +30     

Flag	Coverage Δ
frontend-e2e-test	72.81% <60.71%> (+0.30%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
web/src/pages/Route/constants.ts	100.00% <ø> (ø)
...pages/Route/components/Step1/MatchingRulesView.tsx	51.96% <50.00%> (-0.79%)	⬇️
web/src/pages/Route/service.ts	88.88% <100.00%> (ø)
web/src/pages/Route/transform.ts	72.56% <100.00%> (ø)
web/src/components/Plugin/UI/api-breaker.tsx	62.96% <0.00%> (ø)
web/src/components/Plugin/UI/limit-count.tsx	83.33% <0.00%> (ø)
web/src/components/Plugin/UI/proxy-mirror.tsx	100.00% <0.00%> (ø)
web/src/components/Plugin/UI/limit-req.tsx	100.00% <0.00%> (ø)
...b/src/components/Plugin/UI/referer-restriction.tsx	66.66% <0.00%> (ø)
web/src/components/Plugin/UI/cors.tsx	62.50% <0.00%> (ø)
... and 2 more

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