Added formatter for localization

[axunonb]

Added features to localize literals and placeholders

• Added LocalizationFormatter
• Added ILocalizationProvider and a standard implemention as LocalizationProvider, which handles resx resource files
• SmartSettings were exended with category Localization.
• Custom IFormatter can now make use of localization, if needed.
• New exception type LocalizationFormattingException
• FormattingException now contains InnerException where applicable

[codecov]

Codecov Report

Merging #207 (fd7aa89) into version/v3.0 (45d9fdb) will increase coverage by 1%.
The diff coverage is 100%.

❗ Current head fd7aa89 differs from pull request most recent head 9298f46. Consider uploading reports for the commit 9298f46 to get more accurate results

@@             Coverage Diff              @@
##           version/v3.0    #207   +/-   ##
============================================
+ Coverage            17%     17%   +1%     
============================================
  Files                95      99    +4     
  Lines             12833   12905   +72     
============================================
+ Hits               2146    2224   +78     
+ Misses            10687   10681    -6     

Impacted Files	Coverage Δ
src/SmartFormat/Core/Formatting/FormatDetails.cs	100% <ø> (ø)
...SmartFormat/Core/Formatting/FormattingException.cs	100% <100%> (ø)
src/SmartFormat/Core/Settings/Localization.cs	100% <100%> (ø)
src/SmartFormat/Core/Settings/SmartSettings.cs	65% <100%> (+2%)	⬆️
...rc/SmartFormat/Extensions/LocalizationFormatter.cs	100% <100%> (ø)
...rmat/Extensions/LocalizationFormattingException.cs	100% <100%> (ø)
src/SmartFormat/Extensions/LocalizationProvider.cs	100% <100%> (ø)
src/SmartFormat/SmartFormatter.cs	96% <100%> (ø)
src/SmartFormat/Core/Parsing/Placeholder.cs	96% <0%> (+11%)	⬆️

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[axunonb]

Finally found a fix for the failing unit test, since we have embedded resources in the test project.
The cause was the AltCover package which is used on AppVeyor/CI.

The test now must be invoked with the following additional parameters
dotnet test [...] /p:AltCoverInplace=true /p:AltCoverForce=true