This updates redirected links in integration, update, user
and workflow dirs. Should now link to final URLs to avoid
redirect hops

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

Change assorted absolute links to ce and ee docs
to relative links

Clean out workflow directory by moving images
from gitlab_flow doc to /img

Currently, we label items to be done as "Todo." This is grammatically
incorrect and (therefore) confusing—especially to our Spanish-speaking
users for whom "todo" has a specific and unrelated meaning.

We should use "To Do" and always use it as singular (not "To Dos").

Updates to wording in a few places per MR (ee) discussion

Updating locale/gitlab.pot

Updates to wording in a few places per MR (ee) discussion

Updating locale/gitlab.pot

After review, heading was changed and links to
it needed to be updated, and minor tweaks to
the issues docs such as note formatting

Add backticks around square brackets, or fix links, as necessary.

Changes migration and all other places the attribute is used