Feature: Add -WindowsCompatibleOnly switch parameter to install.ps1

[ev-dev]

Description

Introduces a -WindowsCompatibleOnly switch parameter to the existing install.ps1 PowerShell script to allow a user to specify the installation to only include font files labeled as "Windows Compatible" (as in the font file name contains the explicit string "Windows Compatible").

Requirements / Checklist

• Read the Contributing Guidelines
• Verified the license of any newly added font, glyph, or glyph set

What does this Pull Request (PR) do?

Implements -WindowsCompatibleOnly parameter for install.ps1 and includes example within the help comments in same file

How should this be manually tested?

On a clean Windows machine (no nerd-fonts installed), invoke PS> .\install.ps1 FiraCode -WindowsCompatibleOnly with/without -WhatIf parameter

What are the relevant tickets (if any)?

Closes #840

[Finii]

Shouldn't it anyhow install just the 'normal' set XOR the 'windows compat' set?

I install fonts manually, and I choose only one set, always. Are there reasons to have both sets?

And then, what I always wonder (I'm no Windows user), are there still (relevant) applications on Windows that have these ages-old restrictions on font names, that we need the special truncated names at all? I test the fonts usually on a Windows 10 box, and use VisualStudio and LibreOfficeWriter, and they have no problems with the non-Win-Compat fonts. You obviously want only the compat fonts, so maybe you can enlighten me which application needs them?

[Finii]

I guess this is ok for the time being.

In principle I despise the 'special' Windows Compatible fonts, as they are not really 'special' and double the number of fonts.
I'd rather produce fonts that are universally useful. So maybe they will be dropped some time in the future.

But until that happens...

[Finii]

Fix whitespace errors, force push.

[Finii]

Add Fixes into commit message to enable back-links. Force push (sorry)