Boot Local Task Sanboot by Tag

[ChrisPortman]

Boot Local Task Sanboot by Tag

This adds the option to detect machines that should use the sanboot iPXE
command through the use of a 'sanboot' tag.

Tags allow a policy based approach to selecting the hardware platforms
that require this boot method. For example, creating a sanboot tag that applies
to all HP m300 moonshot cartridges which require the sanboot
method through the use of the 'productname' fact.

[puppetcla]

CLA signed by all contributors.

[smcclellan]

This would be more obfuscated (less likely to have a user accidentally use the tag name) if we made reserved objects have a razor: prefix. So for this example, the tag name should be razor:sanboot.