chore: Add support for toggling blank slate vs forked chain

[sds]

Motivation

We want the ability to start anvil either in forked mode or as a blank slate (for CI tests). Add the logic.

Merge Checklist

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• [x] The PR title adheres to the conventional commits standard
• [x] The PR has been tagged with change type label(s) (i.e. documentation, feature, bugfix, or chore)
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Additional Context

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PR-Codex overview

Focus of the PR:

This PR focuses on adding the option to specify RPC endpoints for the OP testnet and mainnet, and the chain ID for the Anvil container.

Detailed summary:

• Added TESTNET_RPC_URL and MAINNET_RPC_URL environment variables to specify RPC endpoints.
• Added CHAIN_ID environment variable to specify the chain ID.
• Modified the command in docker-compose.yml to handle different scenarios based on the presence of MAINNET_RPC_URL and CHAIN_ID variables.

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[github-actions[bot]]

Coverage after merging sds/add-support-blank-slate into main will be

98.79%

Coverage Report

File	Stmts	Branches	Funcs	Lines	Uncovered Lines
src
Bundler.sol	100%	100%	100%	100%
FnameResolver.sol	100%	100%	100%	100%
IdRegistry.sol	100%	100%	100%	100%
KeyRegistry.sol	100%	100%	100%	100%
StorageRegistry.sol	100%	100%	100%	100%
src/lib
Signatures.sol	100%	100%	100%	100%
TransferHelper.sol	0%	0%	0%	0%	12, 17, 20, 20, 20
TrustedCaller.sol	100%	100%	100%	100%