Manage web pages on PFS github repositories

We now have some intensive descriptions on pfspipe web pages. So, it seems that it's good time to:

• remove subaru-pfs.github.io repository
• move existing replist.html to about.html (pfs_www_pipe)
• add detailed list of repositories with comments and instructions to pfs_www_pipe

switching from github.io will make us feel wanting some simple template processing, but this shall be in other ticket(s) if we want.