Refactor job service to avoid handling a lot of things

[irainia]

Description This issue is part of this discussion. The current (03952e961d54da33aa8daafda45e1d5d3d132d30) job service implementation handles a lot of things, like:

• job spec operation
• job run creation
• job deployment

Maintaining this takes more time than it should.

Acceptance Criteria

• [ ] job service's responsibility should be thin and clear
• [ ] other functionalities outside of the one in the first point is put on their own service

Tech Details

The following is one proposal to be considered to address this issue.

• [ ] break down job service into multiple service according to its responsibility