Make discussion mail lists to public

From allhands #479

Since most of all development process are turned into public (github as public repositories for drp_*, spt_*, ets_*; JIRA at pfspipe is public open), we might be better and possible to make things open, as similar to HSC.
Possible plan is to move into public mailman host at pfspipe.ipmu.jp, and just change domain is possible but could remove -software such as:
allhands-software@pfs.ipmu.jp -> allhands@pfspipe.ipmu.jp
reduction-software@pfs.ipmu.jp -> reduction@pfspipe.ipmu.jp (or drp@pfspipe.ipmu.jp?)
targeting-software@pfs.ipmu.jp -> targeting@pfspipe.ipmu.jp (or survey@pfspipe.ipmu.jp?)
instrument-software@pfs.ipmu.jp -> ics@pfspipe.ipmu.jp