adding factory methods for PathPattern

[noodlze]

This is a draft of my implementation for the issue #659.
I still need to add tests.
I added the following methods:

• PathPattern#endsWith
• PathPattern.under
• PathPattern#of accepting PathPattern... pathPatterns

PathPattern.of(PatternPattern.of("json"), PathPattern.startsWith("/foo/bar"));

I added PathPatternBuilder class to support combining existing patterns:

// /foo/bar/**/*.json
PathPattern.startsWith("/foo/bar").endsWith("json"); // or 
PathPattern.builder()
           .startsWith("/foo/bar")
           .endsWith("json")
           .build();

[CLAassistant]

All committers have signed the CLA.

[codecov]

Codecov Report

Base: 65.71% // Head: 65.56% // Decreases project coverage by -0.16% ⚠️

Coverage data is based on head (3e4eb71) compared to base (bda3bec).
Patch coverage: 0.00% of modified lines in pull request are covered.

Additional details and impacted files

@@             Coverage Diff              @@
##             master     #807      +/-   ##
============================================
- Coverage     65.71%   65.56%   -0.16%     
  Complexity     3289     3289              
============================================
  Files           350      351       +1     
  Lines         13731    13766      +35     
  Branches       1488     1492       +4     
============================================
+ Hits           9024     9026       +2     
- Misses         3863     3896      +33     
  Partials        844      844              

Impacted Files	Coverage Δ
.../com/linecorp/centraldogma/common/PathPattern.java	28.57% <0.00%> (-71.43%)	⬇️
...necorp/centraldogma/common/PathPatternBuilder.java	0.00% <0.00%> (ø)
...ient/armeria/legacy/LegacyCentralDogmaBuilder.java	81.48% <0.00%> (-3.71%)	⬇️
...al/storage/repository/cache/CachingRepository.java	95.31% <0.00%> (+0.78%)	⬆️
...r/internal/admin/auth/FileBasedSessionManager.java	77.69% <0.00%> (+1.43%)	⬆️

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[noodlze]

Replaced by #809