Setup role based access for the data-entry dashboard

[PPrasai]

Feature Description: An authentication system and role based access is required for the data-entry dashboard mentioned in Issue covidsimteam/prox-e#87 Following user roles have been determined to be sufficient:

• Mayor / Admin views overall tasks and creates new users
• Coordinator creates new cases and assigns those cases to case investigators
• Case Investigators fill out Form A, curate a list of potentially exposed individuals and assign follow-up to Contact Tracers
• Contact Tracers fill out Form B1 for every individual assigned by Case Investigators and assigns further follow-up to Follow-up Personnel
• Follow-up Personnel iteratively fill out Form B2 for every individual assigned by Contact Tracers

[risavkarna]

@Cryptokripa, @PPrasai please use the RBAC features already made so far.