fix(#139): removes staking, priority fee still wip

[Alexangelj]

Changes

• Removes stake from Hyper.sol
• Removes unstake from Hyper.sol
• Removes STAKE and UNSTAKE instructions from Enigma.sol.
• Removes STAKE and UNSTAKE branches in Hyper's processing function.
• Updates syncPositionFees to use the already passed in memory variable's liquidity as the input to computing fees earned for the position.
• Removes staked liquidity from position fee syncing liquidity calculation.
• Removes stake and unstake unit tests.
• Removes related staking variables from HyperPool and HyperPosition structs.
• Misc: updates naming of the unused instructions codes to UNSET{number}