[WIP] implement a generic host matcher

[evgeni]

this include matchers for:

• the hostname (based on a regex)
• the host type
• the facts of a host

when comparing facts, different matchers can be configured:

• string - a case insensitive string comparison
• regexp - a regex matcher
• version - the expected value is parsed as a Gem::Requirement and the matcher returns if the Gem::Version representation of the fact value satisfies said requirement

[evgeni]

@mossicrue @Rocco83 when done (it's not yet) this should cover your need to match the OS release etc from the YAML

[mossicrue]

tested and works