Upgrade to Zensical (MK Docs follow up) and other fixes

[moschmdt]

Noteworthy changes next to linting update/ fixes:

• Fixes MKdocs 2.x update will break pipeline - Update or move to zensical #48.
• fix a bug with the outline of the tutorials due to a duplicate h1 heading introduced via the work in progress warning
• four broken links in manual sections 02 and 04 fixed
• footnotes converted to note admonitions for better context placement in manual section
• Usage of caption package for image captions.

Remaining issues that are not fixed, but improved

• figure references (Add figure labels #38)

New version looks like:

@scijones

[scijones]

I admit I didn't go line by line on all the manual changes, but they look like essentially syntax changes. nothing here sends any alarms for me, so thanks!