index: do not mark mrhlpr and mrtest as WIP

mrhlpr is a developer tool, and mrtest is a user-facing tool with very good documentation already. There's no real difference in maturity with pmbootstrap, and mrtest docs is already linked from https://wiki.postmarketos.org/wiki/Mrtest

The only question I have is if we want to make any of the TODOs that were there into issues. But otherwise I see no difference in terms of maturity vs. pmbootstrap.