Many code blocks are 4spaced, and they render in GitLab
without coloring as a result, even though they are
fenced with a language label. If in a list, other items
will render as being in a code block too, even if not
meant to. This fixes all these issues, and cleans up
minor white space issues in install and integration docs

Markdown renderers find it easier to determine
where lists start and end when lists are surrounded
by new lines.

For consistency, also ensure entries in the list
are aligned when they span multipls lines.

[10.6] Fix GitLab Auth0 integration signs in the wrong user

See merge request gitlab/gitlabhq!2354

[ci skip]

[ci skip]

Removed spurious character from Omnibus example