Implement JsonCounter and change CrdtCounter structure

[7hong13]

What this PR does / why we need it?

Implemented JsonCounter and changed CrdtCounter a bit.
(more test code to be added on JsonCounter)

Any background context you want to provide?

changes on CrdtCounter

• Double type is not supported.
• Int and Long overflow is allowed.
• the counterType is determined right after its creation and cannot be changed.

What are the relevant tickets?

Fixes #

Checklist

• Added relevant tests or not required
• Didn't break anything

[codecov]

Codecov Report

Merging #49 (065126f) into main (cff5a7a) will increase coverage by 1.32%.
The diff coverage is 78.18%.

@@            Coverage Diff             @@
##             main      #49      +/-   ##
==========================================
+ Coverage   78.59%   79.92%   +1.32%     
==========================================
  Files          44       45       +1     
  Lines        1733     1758      +25     
  Branches      250      250              
==========================================
+ Hits         1362     1405      +43     
+ Misses        232      206      -26     
- Partials      139      147       +8     

Impacted Files	Coverage Δ
...dev/yorkie/document/operation/IncreaseOperation.kt	71.42% <ø> (+35.71%)	⬆️
yorkie/src/main/kotlin/dev/yorkie/util/Trie.kt	100.00% <ø> (ø)
...src/main/kotlin/dev/yorkie/api/ElementConverter.kt	65.38% <44.44%> (+9.90%)	⬆️
...ain/kotlin/dev/yorkie/document/crdt/CrdtCounter.kt	95.12% <92.85%> (+1.24%)	⬆️
...ain/kotlin/dev/yorkie/document/json/JsonCounter.kt	93.33% <93.33%> (ø)
...ain/kotlin/dev/yorkie/document/json/JsonElement.kt	75.00% <100.00%> (+3.57%)	⬆️
...main/kotlin/dev/yorkie/document/json/JsonObject.kt	91.54% <100.00%> (+0.92%)	⬆️
...kotlin/dev/yorkie/document/json/JsonStringifier.kt	96.77% <0.00%> (+6.45%)	⬆️

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[skhugh]

I think you meant to delete the double type here :)

[skhugh]

since we are only allowing Int and Long for Counter, sanitized seems overcomplicated.
having two invokes for each input type seems to be the better choice now.

[hackerwins]

Thanks for your contribution.