* Groundwork to enable python format checks (via yapf) as part of the CI.
With this change:
* we are set up to use yapf as part of the docker container
* pigweed patch is updated to use the google Python style (pep8 with indent of 2 spaces)
* some documentation updates.
The code still needs to be formatted, and then the Python formatting check will be turned on as part of ci.
BUG=http://b/194404216
* Format all the code.
Once this change is merged, we will turn on Python formatting check as
part of the CI.
* minor formatting update.