ctf: make SIPIE enums store both key and value

ctf: make SIPIE enums store both key and value

By adding the getStringValue and getIntegerValue,
instead of getValue, we have more information available.
This is useful for enums so we can look up the string
name but also sort it easier.

Change-Id: Icfa095a0a8c2b8924809c389dbfe53055c3b63be
Signed-off-by: Matthew Khouzam <matthew.khouzam@ericsson.com>
Reviewed-on: https://git.eclipse.org/r/61814
Reviewed-by: Hudson CI
Reviewed-by: Francis Giraldeau <francis.giraldeau@gmail.com>
Reviewed-by: Patrick Tasse <patrick.tasse@gmail.com>
Tested-by: Patrick Tasse <patrick.tasse@gmail.com>