This is the next the MR !431 (merged)

We are going the move the startComputerPartition from slapos node boot, then if the server is offline or master fail, slapos node instance command will enter in enter on failSafe mode. It will

• Skip processing computer partition with buildout
• will start partition that are in the started state (to make sure that services are running).
• and run promises

Post requests are skipped. getFullComputerInformation request will served from cache, cachecontrol is replaced by requests-cache and offline mode (request only from cache). This help to implement a partial (for now) offline mode on slapos node instance.