Gel RNA QC

With this pull request it performs the basic process for one single rack through the 4 steps (selection, FX, ebase and imager), but still there are some tasks I haven't finished at today. This is the list of the things that still I need to fix sorted by priority:

Important things:
- Add support for more than 1 rack. At now only tested with one single rack.
- Add validation for beds in bed recording
- Upload file to server
- Enable gel creation at server side. Now I'm creating tube_racks.
- Error management
- FX step print button is not correctly added to its linear execution 

Others:
- Use local variables for loading config for bed robots
- Add support for merging children events to linear process
- Refactor bed-verif and recording. It shouldn't have the robot scanner inside its behaviour. This should be managed in the parent component.
- Refactor row_bed_controller. It should be divided in different files (row bed verify, row bed record). 
- Refactor plate creation (number of rows and columns shouldn't be in pipeline.config)
- Correct styles