util/getversion,meson: Add script to allow version info with Meson

Add `util/getversion.sh` that retrieves version information from a
`versioninfo.inc` (what we use for releases) if present or uses
`util/getrevision.sh` if not.

Let Meson use it for flashrom's version. It seems Meson doesn't
generate the manual page at all, so the `--man-date` command is
currently unused.

Change-Id: I401e5638509c4a573bc0cb17ebc5fa76df9700b5
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/35561


Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Mario Limonciello <superm1@gmail.com>
Reviewed-by: Richard Hughes <hughsient@gmail.com>
Reviewed-by: David Hendricks <david.hendricks@gmail.com>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>