Stake Table: Registration

[alysiahuggins]

Create a registration system for validators with a fixed stake amount.

Tasks:

• Implement a function for validators to register with a fixed stake.
• Develop a mechanism to handle registration queues if the validator threshold is met.
• implement epoch logic

[alysiahuggins]

Current plan

• use the existing staketable and write tests for the registration function
• write tests for the registration function as per the modified spec (e.g. validator keys, fixed stake
• override/replace the registration function as per the modified spec
• add tests and implementation for the validator threshold and registration queues