Fully reimplementation of Test Agent

  - Get precise state of all software instances from a Hosting Subscription
  - Get the connection parameters from  all software instances from a Hosting Subscription
  - Get the instance parameters from all software instances from a Hosting Subscription
  - Move all API to connect slapos master to HAL implementation
  - Get the state of the Software Installation
  - Try to connect to monitoring tool in case of error.
  - Use TaskDistributor to determinate the tests (instead local file)
  - Use erp5.util and few erp5testnode features to determinate test revisions.
  - Download informations from the Task distributor instead use parameters (it makes implementation more flexible).