[ADD] Separate Mimir Keys for Admin/Double Spend Chain Halt + Solvency Chain Halt

There should be two separate mimir keys for halting chains:

• One that is enabled by automatic solvency checker: this key should be auto un-halted when solvency is regained
• One that is manually enabled by Node Mimir, admin mimir, or the double-spend check - in this case the chain should remain halted until community devs have investigated and manually un-halted