grammar for identifiers used by the user

Signed-off-by: Markus Pargmann <mpargmann@allfex.org>
id specs: accept intern and data version

Signed-off-by: Markus Pargmann <mpargmann@allfex.org>
pbench: plugin version compare mechanism

Signed-off-by: Markus Pargmann <mpargmann@allfex.org>
pbench: handling of multiple versions

Signed-off-by: Markus Pargmann <mpargmann@allfex.org>
fixup! pbench: plugin version compare mechanism
pbench: Plugin may have arbitrary numbers of component versions

This will introduce component_versions which will help to describe all
versions of used components in this plugin. It creates more reliable
results and an more intuitive user interface to specify versions and
compare benchmark results for different versions.

Signed-off-by: Markus Pargmann <mpargmann@allfex.org>