Remove MAINTAINERS file

Maintainers are listed in the DOAP file, so remove the redundancy (the
reason we needed this file most we because of the autotools build, but
that got removed).
4 jobs for master in 7 minutes and 28 seconds (queued for 1 second)
Status Job ID Name Coverage
  Review
passed #1155224
style-check

00:00:27

 
  Build
passed #1155225
build-folks

00:06:27

 
  Deploy
passed #1155226
pages

00:00:32

passed pages:deploy

00:00:01