File formatting and linting configs

[HumbleDeer]

This changes:

• The default line ending used in markdown and code files for our docs from auto (CRLF or LF depending on OS) to LF (Unix). This helps with keeping git diffs and PR's readable and useful.
• The default linter options for markdownlint are now in the repo
• Recommended plugins/extensions for vscode are now in the repo This also applies to Codespaces using the repo, so spans beyond people using VS Code on their computer alone. Included extensions:
  • Markdownlint (a vscode implementation of markdownlint)
  • VS Code remote containers (for using Codespaces on your local machine; liable to future elaboration
• Formats some remaining CRLF files to LF so they won't interfere with us later on.

For best effect, please set your repository-wide git config to not automatically select line endings:

git config --local core.autocrlf false

[HumbleDeer]

I have a feeling the hard-handed approach of forcing CRLF to LF changes might bother us in the future when we want to hard reset and rebase something.

I'd like kdb's opinion on this, somehow.