Make /EzVz and /ezvz links legacy intercompatible

[HumbleDeer]

cherry-pick from pull request #93 "Minor fixes to documentation STL's and text" ...
... to a new PR so it can either stay open or be handled separately from the other minor fixes as those minor fixes turned out to not be so minor after all.

To view the files changed in this PR, please see https://github.com/VzBoT3D/docs/pull/99/files

The contents of this PR are as follows:

• Adds aliases to pages to restore functionality in the bot
• Adds aliases to pages to make them dummy-proof;
  Examples:
  • add both /ezvz/faq and /ezvz/FAQ
  • add both /ezvz/filaments and /ezvz/Filaments
• Adds slugs and removes permalinks (improves function for the GitHub Pages DNS)
• Adds comments about what were the original links and which are the edited ones.
• addm. above: Fixes some residual issues in pbsuber's quick fixes (multiple commits);
  Example:
  Pbsuper changed /ezvz/how-it-works/customers to /EzVz/how-it-works/customers while the original URL (pre-edits) was actually /EzVz/how_to_customers
  The aliases implemented above set the url's to the more SEO-friendly ones, while keeping compatibility with the old url's the bot (likely) uses

[HumbleDeer]

I'd like both @pbsuper and @StaticFX 's (positive) review on this PR before merging.

[HumbleDeer]

@tehmaze Just confirming you've also checked the contents of these changes? The topic was a bit controversial for a hot second.

[tehmaze]

Confirmed that all the old and new links sort-of work as expected (in that they generate the correct page contents, but I had somehow expected to be redirected). All in all, good enough for now.

[HumbleDeer]

Confirmed that all the old and new links sort-of work as expected (in that they generate the correct page contents, but I had somehow expected to be redirected). All in all, good enough for now.

Were there pages that didn't redirect as expected, then? Did you test this with a local deployment?

Edit: I just checked with a local deployment and it looks like all the redirects work.
I did also, during this, discover I didn't change any of the URL's that link to /EzVz pages but that's also the only reason I could see the redirects at work, working properly. I'll try and fix these links soon ish, hopefully. This is implemented in a succeeding commit.

Do we merge this and put those fixed text links in a new PR, or fix those in here?

New commits were added after review