[ux] install scripts: POSIX compliance + optional tooling support

[winstonwumbo]

New Features

• Refactored haxthewebme.sh to achieve POSIX-compliance. The original script used several "Bashisms", i.e. functions exclusive to the Bash shell
  • While this works in most places practically (Bash is installed everywhere), POSIX-compliance ensures haxthewebme.sh is portable across all edge cases
• Added new function to haxthewebme.sh and haxthewebme.ps1: Option to automatically configure advanced HAX tooling (symlink-dir, lerna, etc.)
• Improved Git handling in haxthewebme.ps1
  • Properly handles existing webcomponents directory
  • Asks user whether to automatically install, then configure Git CLI
• Added function to mirror yarn.lock deletion from haxthewebme.sh in haxthewebme.ps1

[vercel]

@winstonwumbo is attempting to deploy a commit to the HAXTheWeb Team on Vercel.

A member of the Team first needs to authorize it.

[btopro]

Love all these DX improvements.sir