Fetch maintainer information in one query

Fetch maintainer information in one query

Viewing the /project/ page lists maintainers. Prior to this patch,
this was done in one query to fetch the maintainer IDs, and then one
query per mainatiner to get the name/email address.

Now, with this patch, it's all in one query (yay joins) and saves
a few ms of database queries for displaying the page.

Realistically, this doesn't save us too much time as counting how many
patches are there takes 99% of the database time for this page.

Signed-off-by: Stewart Smith <stewart@linux.ibm.com>
Reviewed-by: Stephen Finucane <stephen@that.guru>