We should probably restructure the validation process

[mpsonntag]

We should probably restructure the validation process

• Once a validation has started, the service should create a processing badge for the commit and return, so the user does not have to wait until cloning and validation is done (which might take some time).
• Currently a validation process never returns an error. If something goes wrong during the validation an error should be returned here; if an error is present, the service should then replace the processing badge with an appropriate error badge. If no error is present it is assumed that the build went through and an appropriate badge has been created by the validation process.

Originally posted by @mpsonntag in #33