feat: Add "Requests" filter option for package name

• Add package name textbox for filtering requests (with auto-suggest)
• Make "x pending requests" a link for TU/Dev on the package details page
  (linking to the requests page, pre-filtered with the pkg name)
• .gitignore - add test mails directory (not related to this feature)

Issue-report/Feature-request: IRC conversation. @jelle and @gromit want this 😉

Signed-off-by: moson-mo mo-son@mailbox.org