[BB-7375] Trial Project based recruitment process

In this MR we replace the Trial Period with the Trial Project based recruitment process. This includes a number of changes from !355 (closed) and a few improvements to the process based on recent experiences.

The new recruitment process -

1. Prepare a list of trial projects
2. Preselection of candidates
3. Interview 1 (Recruitment Managers)
4. Review & Selection of candidates from Interview 1
5. Interview 2 (Admin Specialist)
6. Selection of candidates from Interview 2
7. Signing Contract
8. Assignation of trial project
9. Review of trial project
10. Start of Onboarding Period (2 months)
11. Screening review after 10 days
12. Developer Review after 2 months