feat: delegation state transition

[gusin13]

This PR

1. Implements phase 2 delegation state transition
   If the staker is following old flow, the state transitions will be Pending -> Active -> Unbonded
   If the staker if following the new pre-approval flow, it will be Pending -> Verified -> Active -> Unbonded

2. Indexer will now panic and exit/stop everything if encountered any error in processing events.

3. Improves validation functions.

Notes

• came across a bug have created a ticket - ref
• have some doubts in certain states in babylon, opened a slack thread ref. Basically babylon stakers can follow either old flow/ or the new pre-approval flow which is why i was getting confused earlier. the inclusion proof is optional in MsgCreateBTCDelegation ref.
  State transition in this pr performs certain validations and first identifies if the staker is following old flow or new flow and then perform appropriate transition. This is in sync with Babylon's logic ref ref2