Tests may want to parse their own arguments. Refactor the parser code to
support this and allow settings to receive arguments as well.

Signed-off-by: Simon Glass <sjg@chromium.org>

The patman directory has a number of modules which are used by other tools
in U-Boot. This makes it hard to package the tools using pypi since the
common files must be copied along with the tool that uses them.

To address this, move these files into a new u_boot_pylib library. This
can be packaged separately and listed as a dependency of each tool.

Signed-off-by: Simon Glass <sjg@chromium.org>

This enables versioning a project specific patman configuration file.
It also makes it possible to declare the project name, which is not a
useful thing to do in $HOME/.patman.  A new test is added, along
updated documentation.

Signed-off-by: Maxim Cournoyer <maxim.cournoyer@savoirfairelinux.com>
Reviewed-by: Simon Glass <sjg@chromium.org>