This commit deletes the old implementation to assist in cleaner code reviews of
the upcoming reimplementation.
This commit also moves YARD to version 0.9.5 and lays down a bare bones
implementation of Puppet Strings that currently does nothing.
Since we don't want the name of the tool to reflect the fact that
it is using yard internally (this is an implementation detail), rename
the face to `strings`. Now when one wishes to generate documentation,
`puppet strings` will be used rather than `puppet yardoc`.