[ADD] docker file and shippable compatibility

Docker odoo image
Building here
[ocaimages/oca-odoo](https://registry.hub.docker.com/u/ocaimages/oca-odoo/builds_history/91750/)
You misunderstood me.
In dockerfiles, having two RUN commands generates two intermediate images.
You have two runs calling apt-get, therefore you change the state of the machine in the same with (calling apt-get).
Having all your apt-gets under one RUN results in faster compilation since you only have to warm up the UNION FS once instead of twice.