Fully remove CGT code from L1 contracts (OPCM - Upgrade 13)

[maurelian]

Description

Build on the work begun in #13589 to completely remove cgt code from L1 code paths. No further work should be done to L2 code paths.

The full set of ABI changes from CGT can be seen here: https://github.com/ethereum-optimism/optimism/pull/10143/files#diff-97745aae7f1af56cec3629873b886e53b94123dedbae6b3db26babb1ed50354b

We should remove all newly added functions (including getters) on L1 contracts. However we should minimize changes to the initialize() functions (meaning it is fine to keep the systemConfig address as a new input to the bridge contracts, and as a state var, but it should become internal).

Specifically:

• In L1CrossDomainMessenger:
  • make the systemConfig variable internal
  • keep the _systemConfig argument
• In L1StandardBridge:
  • make the systemConfig variable internal
  • keep the _systemConfig argument
• In SystemConfig
  • remove gasPayingToken()
  • remove isCustomGasToken()
  • remove gasPayingTokenName()
  • remove gasPayingTokenSymbol()
  • remove _setGasPayingToken()
  • remove gasPayingToken from Addresses struct
• In OptimismPortal:
  • remove balance()
  • remove depositERC20Transaction()
  • remove setGasPayingToken()

Note that the SystemConfig should be the only contract with changes to the initializer.

In the above contracts, unused branching code, errors and events should also be removed.

Where state vars are removed a spacer should be added.

[mds1]

Where state vars are removed a spacer should be added.

@AmadiMichael In case you aren't familiar, info on our spacing naming convention here: https://github.com/ethereum-optimism/optimism/blob/develop/packages/contracts-bedrock/meta/STYLE_GUIDE.md#spacers

[zhiqiangxu]

When will CGT be added back again?