Add new value binding methods (UnixTimeMilli,TextUnmarshaler,JSONUnmarshaler) to Valuebinder

[aldas]

Add new value binding methods (UnixTimeMilli,TextUnmarshaler,JSONUnmarshaler) to Valuebinder. As it adds only new methods to struct it is backwards compatible change.

• UnixTimeMilli binds 1647184410140 to 2022-03-13T15:13:30.140000000+00:00 useful when dealing with Javascript

• TextUnmarshaler binds value to destination implementing encoding.TextUnmarshaler interface

• JSONUnmarshaler binds value to destination implementing json.Unmarshaler interface

Requested in #2000 (comment)

[codecov]

Codecov Report

Merging #2127 (bfea350) into master (3f5b733) will increase coverage by 0.11%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #2127      +/-   ##
==========================================
+ Coverage   92.10%   92.21%   +0.11%     
==========================================
  Files          37       37              
  Lines        3028     3071      +43     
==========================================
+ Hits         2789     2832      +43     
  Misses        150      150              
  Partials       89       89              

Impacted Files	Coverage Δ
binder.go	100.00% <100.00%> (ø)
echo.go	95.17% <0.00%> (+0.03%)	⬆️
middleware/recover.go	85.00% <0.00%> (+0.78%)	⬆️

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[aldas]

@lammel please review

[lammel]

Looks good to me. Fine work @aldas
Haven't had time to actually do some testing, but test cases look good anyway.