Turn code block into example

See merge request !1062

Spring cleaning: node-local storage and old filesystems

See merge request !1060

Remove recabling hint from Power9 section

See merge request !1059

- Slurm:
  - filesystem features removed, since they are currently not active
  - Add table with information on node-local storage for all clusters
- Beegfs_global0 removed from workspace setting table
- Rework some links
- Add new page on outdated filesystems in the archive and started moving content to this page

Filesystem feature not working: add warning and hint

See merge request !1058

Follow Noah's sugesstions in !1054

See merge request !1056

Update Access and Login Pages

See merge request !1054

- Use hint boxes for steps in Jards
- Consistent usage of note boxes for application ways
- Fix indent

- Spell: Use "NHR Center" as on ZIH web site
- Lint:
  - Fix line length and compact lines where useful
  - newline after headings
  - Remove level five headings for styling
layout: Avoid arrows; connect links and desc. using linking words