fix(formatter): add possibility to parse a date formatter as a UTC date

[ghiscoding]

• e.g. when '2099-12-31T00:00:00.000Z' in my TZ (EST) the DateIso Formatter will transform this in 2099-12-30 instead of 2099-12-31 because it assumes that the TZ must be included

[codecov]

Codecov Report

Merging #511 into master will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master      #511   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          148       148           
  Lines         9586      9589    +3     
  Branches      3341      3344    +3     
=========================================
+ Hits          9586      9589    +3     

Impacted Files	Coverage Δ
...angular-slickgrid/formatters/formatterUtilities.ts	100.00% <100.00%> (ø)

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