[Area 1] Inline setup markdown migration (#6074)

* delete setup page

* moved pdf to markdown
created setup folder

* removed old pdf files

* added office pic

* added guite pic

* added cisco area1 mx pic

* added cisco mx pic

* Apply suggestions from code review

Co-authored-by: angelampcosta <92738954+angelampcosta@users.noreply.github.com>

* added redirects for deletes pdfs

* monospaced hosts

* refined text

* Update content/email-security/deployment/inline/setup/cisco-area1-mx.md

Co-authored-by: angelampcosta <92738954+angelampcosta@users.noreply.github.com>

Co-authored-by: angelampcosta <92738954+angelampcosta@users.noreply.github.com>