Add developer MOTD (bug 945956)

needs ACL

implemented motd for My Submissions page

added menu to set developer motd

added migration

respond to review feedback

make PEP 8 happy

import permission_required before using

added tests

refactored tests

pep 8 fixes

respond to feedback

address review issues

cache close button

collapse the ifs

capitalize the words

bad idea to have motd variable inside motd method

remove newlines, extrapolate motd

reverting a one-line fix that had nothing to do with this bug

add some breathing room to motd

elicidate comment

rename test

rename test

punctuation and spacing

capitalization

chain all the things

resolve regression with reviewer tools motd close button

move link to edit motd

prettify the save button
Merge pull request #2376 from dethe/developer_motd

Add developer MOTD (bug 945956)