Feature: Improved Windows console text handling

[dragonmux]

This PR aims to improve how we handle strings in console_t/consoleStream_t on Windows and in general Unicode handling on output.

This fixes an issue where std::string's containing UTF-8 would not get converted on Windows, resulting in garbled output.

We also implement support for std::wstring/wchar_t and std::u16String/char16_t strings though the former is only for Windows. This should allow any UTF-16 or wide Windows character strings to be correctly displayed in a program's output just the same as any other strings.

Some of the architectural changes should also provide a nice speed boost for STL string containers by not throwing away the length information only to have to re-calculate it.

[codecov]

Codecov Report

Merging #79 (fb4dbe0) into main (c94ee1d) will decrease coverage by 0.62%.
The diff coverage is 19.69%.

@@            Coverage Diff             @@
##             main      #79      +/-   ##
==========================================
- Coverage   90.38%   89.77%   -0.62%     
==========================================
  Files          47       47              
  Lines        3277     3414     +137     
  Branches      644      660      +16     
==========================================
+ Hits         2962     3065     +103     
- Misses        247      313      +66     
+ Partials       68       36      -32     

Files	Coverage Δ
impl/socket.cxx	83.33% <ø> (ø)
substrate/console	95.06% <33.33%> (-1.19%)	⬇️
impl/console.cxx	59.88% <19.04%> (-18.31%)	⬇️

... and 8 files with indirect coverage changes

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[amyspark]

Apart from the test suite needing some love, there is one issue that requires sorting out.