Many minor updates

We have updated new small features, as well as bug fixes over the last months.

The following bugs were fixed:

• Fix an epoch calculation error on handleEpochLengthUpdate
• Added the handleRewardsDenyListUpdated to the manifest. It was not there, and thus, not triggering when we were testing it.

The following was changed:

• Swapped stakedIndexersCount subtraction from withdraw to locked
• Refactored the updateDelegationExchangeRate() code to be cleaner, and truncate all delegation exchange ratios to 18 decimals. This makes it much easier to handle in the front end, and anything past 18 decimals was useless information since we have no precision beyond the smallest unit of GRT.

The following was added to the subgraph:

• Query fee effective cut. This is very similar to indexer reward effective cut, which is explained well in 0.7.0's tag. This is the same, but for query fees
• Added lastDelegatedAt and lastUndelegatedAt for the DelegatedStake entity
• Added github actions for deploying the subgraph when specific branches (testnet, mainnet, mainnet-staging) are updated