GDRCopy version 2.0

Changelog:

• Harden security in gdrdrv.
• Enable cached mappings in POWER9.
• Improve copy performance with unrolling in POWERPC.
• Consolidate basic and validate into a new functional and security test, sanity.
• Introduce compile time and runtime version checking in libgdrapi.
• Introduce both RPM and deb packaging for the userspace library as well as the sample/test applications.
• Introduce dkms packaging for the gdrdrv driver.
• Rename two APIs, i.e. gdr_copy_from/to_bar to gdr_copy_from/to_mapping.
• Update README