* feat: op-program supports custom chain config

* address comments

* address comments

* update mainnet.go/sepolia.go

* Update op-program/chainconfig/chaincfg.go
Co-authored-by: Adrian Sutton <adrian@symphonious.net>

* more error info on config file not found

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Co-authored-by: Qi Zhou <qizhou@ethstorage.io>
Co-authored-by: Adrian Sutton <adrian@symphonious.net>