Creates third-party-requests mailing list

The previous patch deleted the entry for the third-party-request
mailing list since -request is a reserved word on the mailing
list server. This patch adds the list entry back with the name
third-party-requests, which should avoid a word usage clash with
the mail server.

Change-Id: I91cc67ba87c1deb1f21fa102f4051934cf9d890d
Merge "Creates third-party-requests mailing list"