feat: upgradable contracts

[shaspitz]

Closes #10

• Makes all contracts OwnableUpgradable
• Removes Create2, as it isn't compatible with upgradable contract deployment, and will be replaced by ENS + create3 #45
• Standardizes all contracts to use solidity 0.8.20
• Changes Preconfirmations.sol to be named PreConfCommitmentStore.go (matching the contract name itself) as was required for new method of deployment
• Hardcodes two common values for constructAndStoreCommitment in OracleTest.sol to avoid stack overflow errors

[shaspitz]

This change was neccessary to avoid the following error:

forge clean && forge test --via-ir
[⠊] Compiling...
[⠔] Compiling 81 files with Solc 0.8.23
[⠘] Solc 0.8.23 finished in 34.96s
Error:
Compiler run failed:
Error: Yul exception:Cannot swap Variable var_decayStartTimestamp with Variable _9: too deep in the stack by 2 slots in [ RET var_txnHash_64919_mpos var_decayStartTimestamp var_decayEndTimestamp var_blockNumber var_decayStartTimestamp var_bid var_provider var_signerPk expr_64966_mpos expr_64939_address var_dispatchTimestamp expr_64939_address var_blockNumber var_bid var_txnHash_64919_mpos expr_64983_mpos expr_64980_mpos expr var_decayEndTimestamp _9 ]
No memoryguard was present. Consider using memory-safe assembly only and annotating it via 'assembly ("memory-safe") { ... }'.
YulException: Cannot swap Variable var_decayStartTimestamp with Variable _9: too deep in the stack by 2 slots in [ RET var_txnHash_64919_mpos var_decayStartTimestamp var_decayEndTimestamp var_blockNumber var_decayStartTimestamp var_bid var_provider var_signerPk expr_64966_mpos expr_64939_address var_dispatchTimestamp expr_64939_address var_blockNumber var_bid var_txnHash_64919_mpos expr_64983_mpos expr_64980_mpos expr var_decayEndTimestamp _9 ]
No memoryguard was present. Consider using memory-safe assembly only and annotating it via 'assembly ("memory-safe") { ... }'.

[Mikelle]

left over some nits, but overall looks good to me!