Remove unneeded trailing whitespace in lines in
/development /ci /api and /administration docs.

All code blocks should be surrounded by blank lines

Also fixes instances in Markdown that broke the rule.

Previously, we used brackets to denote the tier badges,
but this made Kramdown, the docs site Markdown renderer,
show many warnings when building the site. This is now
fixed by using parentheses instead of square brackets.

This was caused by [PREMIUM] looking like a link to
Kramdown, which couldn't find a URL there.

See:
- https://gitlab.com/gitlab-com/gitlab-docs/merge_requests/484
- https://gitlab.com/gitlab-org/gitlab-ce/issues/63800

First MR in a series updating all redirected links
in CE documentation to the destination URLs

Also adds and one linting rule
and makes project conform to it.

Docs: Convert absolute links to relative in /ci docs

See merge request gitlab-org/gitlab-ce!29029