Cleanup: Decide on consistent revert message format about v3-staker

[omarish]

Proposed messages (all from UniswapV3Staker.sol). What do you think @ewilz @moodysalem ?

The proposed messages are a little verbose. If the contract is too big, here's what we will do to reduce it:

1. Change all the UniswapV3Staker:: prefixes to Staker:
2. Omit the Staker: prefix
3. Omit the function names
4. Make descriptions more terse

Before	After
claimDeadline_not_gte_endTime	UniswapV3Staker::createIncentive: claim deadline before end time
endTime_not_gte_startTime	UniswapV3Staker::createIncentive: end time before start time
INCENTIVE_EXISTS	UniswapV3Staker::createIncentive: incentive already exists
INVALID_REWARD_ADDRESS	UniswapV3Staker::createIncentive: invalid reward address
INVALID_REWARD_AMOUNT	UniswapV3Staker::createIncentive: invalid reward amount
REWARD_TRANSFER_FAILED	UniswapV3Staker::createIncentive: reward transfer failed
TIMESTAMP_LTE_CLAIMDEADLINE	UniswapV3Staker::endIncentive: claim deadline before block timestamp
INVALID_INCENTIVE	UniswapV3Staker::endIncentive: incentive is invalid
uniswap v3 nft only	UniswapV3Staker::onERC721Received: uniswap v3 nft only
NUMBER_OF_STAKES_NOT_ZERO	UniswapV3Staker::withdrawToken: nonzero number of stakes
NOT_YOUR_NFT	UniswapV3Staker::withdrawToken: nft does not belong to msg.sender
NOT_YOUR_DEPOSIT	UniswapV3Staker::stakeToken: deposit owner is not msg.sender
INVALID_POSITION	UniswapV3Staker::unstakeToken: specified position is invalid
BAD INCENTIVE	UniswapV3Staker::unstakeToken: incentive not found
non-existent incentive	UniswapV3Staker::_stakeToken: incentive not found

[visavishesh]

I would propose the following if the goal is to be terse / save bytespace. Added a few recent ones to this list. All have been made shorter where possible, except for already staked which I proposed "incentive already staked".

Before	After
claimDeadline_not_gte_endTime	claim deadline before end time
endTime_not_gte_startTime	end time before start
INCENTIVE_EXISTS	incentive already exists
INVALID_REWARD_ADDRESS	invalid reward address
INVALID_REWARD_AMOUNT	invalid reward amount
REWARD_TRANSFER_FAILED	reward transfer failed
TIMESTAMP_LTE_CLAIMDEADLINE	claim deadline before block time
INVALID_INCENTIVE	invalid incentive
uniswap v3 nft only	not a univ3 nft
NUMBER_OF_STAKES_NOT_ZERO	nonzero num of stakes
NOT_YOUR_NFT	sender is not nft owner
NOT_YOUR_DEPOSIT	sender is not deposit owner
INVALID_POSITION	position is invalid
BAD INCENTIVE	incentive not found
non-existent incentive	incentive not found
Stake does not exist	nonexistent stake
incentive not started yet	incentive not started
incentive ended	incentive ended
already staked	incentive already staked

[omarish]

These messages look good.

If we have the space, it might be good to prefix them with the function name (invalid incentive would become createIncentive: invalid incentive), but I don't feel strongly about that.

@ewilz @moodysalem looks good to you?