devtools: remove useless files from ABI reference

devtools: remove useless files from ABI reference

When building an ABI reference with meson, some static libraries
are built and linked in apps. They are useless and take a lot of space.
Those binaries, and other useless files (examples and doc files)
in the share/ directory, are removed after being installed.

In order to save time when building the ABI reference,
the examples (which are not installed anyway) are not compiled.

Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
Acked-by: David Marchand <david.marchand@redhat.com>