[Buildbot] #3560: implement plugin for serving static files (equivalent of 0.8 `public_html`)

[Buildbot trac]

#3560: implement plugin for serving static files (equivalent of 0.8 `public_html`)
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Reporter:  rutsky     |      Owner:
    Type:  undecided  |     Status:  new
Priority:  major      |  Milestone:  0.9.+
 Version:  master     |   Keywords:
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 Buildbot 0.9.0 doesn't use/need `public_html` for it's function, so it was
 removed.

 Users transitioning from 0.8 might depend on serving static files in
 `public_html`, and having third party web server might be unexpected and
 unwelcome for some users for their simple use cases.

 Lets add Buildbot plugin that allows to serve static files in similar
 fashion to 0.8's `public_html`.

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Ticket URL: <http://trac.buildbot.net/ticket/3560>
Buildbot <http://buildbot.net/>
Buildbot: build/test automation