package/python-lockfile: new package

package/python-lockfile: new package

The lockfile package exports a LockFile class which provides a
simple API for locking files. Unlike the Windows
msvcrt.locking function, the fcntl.lockf and flock functions,
and the deprecated posixfile module, the API is identical
across both Unix (including Linux and Mac) and Windows
platforms.

The lock mechanism relies on the atomic nature of the link
(on Unix) and mkdir (on Windows) system calls. An
implementation based on SQLite is also provided, more as a
demonstration of the possibilities it provides than as
production-quality code.

Signed-off-by: Adam Duskett <aduskett@greenlots.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>