L1 Substreams feature parity

[sahra-karakoc]

Replicating the functionality

https://github.com/graphprotocol/graph-network-subgraph/blob/0154622d67522dbd1f5026dcf50abad2069f5588/src/mappings/l1staking.ts

https://github.com/graphprotocol/graph-network-subgraph/blob/0154622d67522dbd1f5026dcf50abad2069f5588/src/mappings/l1gns.ts

Fields to change

• indexer.stakedTokens
• graphNetwork.totalTokensStaked
• indexer.delegatedTokens
• graphNetwork.totalDelegatedTokens
• graphNetwork.totalTokensSignalled

Fields to add

Tracking issue

#61