[CI & docs] Rework of analysis docs + improved checks

[chalin]

• Contributes to #247
• Adds markdown linter + GH action
• Runs markdown linter over all files, except old project analyses (it will check new analyses). Fixes done, and included in this PR.
• Includes result of review and slight rework of templates (a few file renames).
• Fixes broken links

[chalin]

I think linting the old project analyses is a good idea too (for later).

Where do you set the targets/filters for the linter?

In the NPM scripts.

I can't get the file filtering to work inside GH actions (it works locally), so I'm going to ignore all analyses for now.

[nate-double-u]

I can't get the file filtering to work inside GH actions (it works locally), so I'm going to ignore all analyses for now.

@RobertKielty, maybe you could take a look?

[chalin]

All good. Checks are green. Merging.