feat(datepicker): added Thai locale support for datepicker

[tumit]

PR Checklist

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• read and followed the CONTRIBUTING.md guide.
• built and tested the changes locally.
• added/updated tests.
• added/updated API documentation.
• added/updated demos.

[codecov]

Codecov Report

Merging #3409 into development will decrease coverage by 0.34%.
The diff coverage is 66.66%.

@@               Coverage Diff               @@
##           development    #3409      +/-   ##
===============================================
- Coverage        72.83%   72.48%   -0.35%     
===============================================
  Files              248      249       +1     
  Lines             8009     8060      +51     
  Branches          1412     1527     +115     
===============================================
+ Hits              5833     5842       +9     
+ Misses            1823     1795      -28     
- Partials           353      423      +70

Impacted Files	Coverage Δ
src/index.ts	100% <100%> (ø)	⬆️
src/locale.ts	100% <100%> (ø)	⬆️
src/bs-moment/i18n/th.ts	33.33% <33.33%> (ø)
src/dropdown/bs-dropdown-menu.directive.ts	71.42% <0%> (-28.58%)	⬇️
src/tabs/tab-heading.directive.ts	66.66% <0%> (-13.34%)	⬇️
src/popover/popover-container.component.ts	90.9% <0%> (-9.1%)	⬇️
src/carousel/slide.component.ts	91.66% <0%> (-8.34%)	⬇️
src/tabs/ng-transclude.directive.ts	60% <0%> (-6.67%)	⬇️
src/popover/popover.directive.ts	82.14% <0%> (-6.32%)	⬇️
src/progressbar/progressbar.component.ts	93.75% <0%> (-6.25%)	⬇️
... and 33 more

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