[Buildbot] #3120: Add capabilities to slaves

[Buildbot trac]

#3120: Add capabilities to slaves
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Reporter:  tardyp       |      Owner:
    Type:  enhancement  |     Status:  new
Priority:  minor        |  Milestone:  0.9.+
 Version:  master       |   Keywords:
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 Adding generic 'capabilities' to slaves will simplify a lot of usecases in
 buildbot.

 capabilities are key=value(s) associated to a slave, e.g
 os=linux
 db=[mysql, postgreesql]

 a builderConfig would accept a new requiredCapabilities= argument, that
 would make slavenames unneeded

 requiredCapabilities is a dict or a lambda buildrequest: dict, for finding
 the needed capabilities dynamically.

 Capabilities are stored in the db for slaves, and can be displayed (and
 eventually edited) in the UI

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Ticket URL: <http://trac.buildbot.net/ticket/3120>
Buildbot <http://buildbot.net/>
Buildbot: build/test automation