Add Mexc and other new methods

[IlyaVshivtsev]

Pull request checklist

• Did you bump the project version?
• Did you add a description to the Pull Request?
• Did you add new tests?
• Did you add reviewers?

[codecov-commenter]

Codecov Report

❌ Patch coverage is 8.79121% with 166 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (release/v0.35.0@ee87c6b). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
src/Mexc/Mexc.jl	3.63%	53 Missing ⚠️
src/Mexc/Errors.jl	0.00%	26 Missing ⚠️
src/Bitget/API/V2/Mix/Market/Contracts.jl	0.00%	12 Missing ⚠️
src/Mexc/API/V3/ExchangeInfo.jl	0.00%	12 Missing ⚠️
src/Mexc/API/V1/Contract/Detail.jl	0.00%	9 Missing ⚠️
src/Bitget/API/V2/Mix/Market/OpenInterest.jl	0.00%	8 Missing ⚠️
src/Bitget/API/V2/Mix/Market/Tickers.jl	0.00%	8 Missing ⚠️
src/Mexc/Utils.jl	0.00%	8 Missing ⚠️
src/Mexc/API/V3/Ticker24hr.jl	0.00%	6 Missing ⚠️
.../API/Internal/Withdrawals/Public/WithdrawalInfo.jl	0.00%	5 Missing ⚠️
... and 6 more

Additional details and impacted files

@@                Coverage Diff                @@
##             release/v0.35.0     #88   +/-   ##
=================================================
  Coverage                   ?   4.77%           
=================================================
  Files                      ?     316           
  Lines                      ?    2931           
  Branches                   ?       0           
=================================================
  Hits                       ?     140           
  Misses                     ?    2791           
  Partials                   ?       0           

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