patman: Move library functions into a library directory

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>

binman: Make the tooldir configurable

Add a command-line argument for setting the tooldir, so that the default
can be overridden. Add this directory to the toolpath automatically.
Create the directory if it does not already exist.

Put the default in the argument parser instead of the class, so that it
is more obvious.

Update a few tests that expect the utility name to be provided without
any path (e.g. 'futility'), so they can accept a path, e.g.
/path/to/futility

Update the documentation and add a few tests.

Improve the help for --toolpath while we are here.

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

binman: Move the tools directory into the Bintool class

We want to be able to change this directory. Use a class member to hold
the value, since changing a constant is not good.

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

patman: Convert camel case in tools.py

Convert this file to snake case and update all files which use it.

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

binman: Add tests for bintool

Add tests to cover the bintool functionality.

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

patman: Convert camel case in tools.py

Convert this file to snake case and update all files which use it.

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

binman: Add tests for bintool

Add tests to cover the bintool functionality.

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

binman: Add tests for bintool

Add tests to cover the bintool functionality.

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