Improve docs (overview)

[rdnfn]

Problem

The documentation can always be improved.

Solution

Add the following parts and improvements to the docs:

• Env list
  • #38 (priority)
  • #42
  • #45
• Other
  • #78 (priority)
  • #37
  • #73
  • #69
  • #76
  • #75
  • #79

For the first three issues it is important to setup a solid parsing pipeline from google drive and beobench_contrib repo. Further each integration should have its own page to make the pages more readable with one overview page with full env list.