docs: site build corrections, shared doc scrub, and new content

[EisenbergEffect]

Description

A collection of updates to the documentation build and content.

Motivation & context

There were a few bugs and omissions in the original docs build setup which needed to be fixed. As part of that work, several documents were more correctly integrated and cleaned up. Here's a list of what this PR includes:

• Fixed the prepare-docs script so that it works on both Mac and Windows
• Enabled the prepare-docs script to copy special markdown files from various locations in the repo, stripping the markdown h1s and merging them with standard yaml metadata. The special docs include: code of conduct, contributing, license, security, and acknowledements.
• Enabled prepare-docs to filter out specific component docs for components we aren't ready to make public.
• Fixed a number of async issues in prepare-docs.
• Added more thorough handling of non-existent directory structures during file copy operations in prepare-docs.
• Removed the docs temp folder from source control.
• Broke out the fast-element documentation into its individual pages, fixing code formatting and added admonitions.
• Wrote the Getting Started and Next Steps articles for fast-element.
• Wrote the community/join article.
• Updated the community/contributor-guide article to include machine and tool setup, along with corrections to commands and procedures for web components.
• Updated the community/writing-documentation article to include basics of markdown and api documentation, along with instructions on how to test documentation locally.
• Wrote the resources/browser-support article.
• Wrote the resources/glossary article.
• Wrote the resources/faq article.

Note: The bulk of the deleted files are the removal of the docs temp folder from source control.

Issue type checklist

• Chore: A change that does not impact distributed packages.
• Bug fix: A change that fixes an issue, link to the issue above.
• New feature: A change that adds functionality.
• Documentation: Additions or improvements to documentation.

Process & policy checklist

• I have added tests for my changes.
• I have tested my changes.
• I have updated the project documentation to reflect my changes.
• I have read the CONTRIBUTING documentation and followed the standards for this project.

[awentzel]

Should this template instead leverage semantic HTML rather than DIVs with classes?

?

[awentzel]

You may want to explain the acronym for CSP.

[awentzel]

Same templating concern as commented on previously with reliance on divs over semantics.