patman: Add reading of series and patch status

Expand the patchwork module so that it can match the current
requirements of the 'patman status' command, i.e. reading the state of a
series and the patches associated with it.

Since the format of each patchwork response is a little tricky to
understand, add examples in comments at the top of each function.

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