This commit aims to replace static jobs by fully configurable build config.
Each build has a config (custom or inherited from repo or branch).
Each config has a list of steps.
For now, a step can test/run odoo or create a new child build. A python job is
also available.
The mimic the previous behaviour of runbot, a default config is available with
three steps, an install of base, an install+test of all modules, and a last step
for run.
Multibuilds are replace by a config containing cretaion steps.
The created builds are not displayed in main views, but are available
on parent build log page. The result of a parent takes the result of
all children into account.
This new mechanics will help to create some custom behaviours for specifics
use cases, and latter help to parallelise work.
The previous code of runbot and runbot_cla was made for Odoo API version
8.0. This commit makes it work with Odoo API 11.0 and Python 3.
Also, the present refactoring splits the code into multiple files to
make it easier to read (I hope).
The main change due to Python 3 is the job locking mechanism:
Since PEP-446 file descriptors are non-inheritable by default.
A new method (os.set_inheritable) was introduced to explicitely make
fd inheritable. Also, the close_fds parameter of the subprocess.Popen
method is now True by default.
Finally, PEP-3151 changed the exception raised by fcntl.flock from IOError to OSError
(and IOError became an alias of OSError).
As a consequence of all that, the runbot locking mechanism to check if a
job is finished was not working in python3.
