Seeded database with initial roles

[jacobatan]

Closes: #113

What was done:

• Seeded database with initial Roles
• 1st user gets an admin role
• Other users get default role, thereby removing the error on the profile page
• Implemented services pattern
• Made Default and Admin roles immutable

How to test:

• [x] Change the mongo_uri to a different db instance.
• [x] And login with the first account => This account should have the Admin role.
• [x] Login with your second account => This account should have the Default role.
• [x] Try to edit the Default and Admin roles, it shouldn't save