Add a GovStore fallback rule to redirect /* to its GOV.UK start page

- If and only if the path does not match any of the previous regexen -
  see
  https://github.com/alphagov/bouncer/commit/c29b447b63389d0b2d7f230565ae1b847481f01d.
- This encompasses /cloudstore/supplier, so delete that rule.
Yeah, that seems OK, apart from in the case where we have suppliers just directly underneath /cloudstore. Amended with that little addition.