indexer-agent,-common: Use consistent clear network/epoch var naming

[fordN]

Main changes:

• Update network identifier and epoch variable names to improve clarity and consistency as we move to a more complex multi-chain world.
• Use the user provided network name rather than the JSON-RPC provider returned network name when resolving POIs.

I also included some more general code organization improvements.

• Moved type definitions that have been accumulating in the allocations module in indexer-common to a more general types file.
• Remove redundant variables in a few places.
• Include components name in logger passed into ActionManager and AllocationManager.

[hopeyen]

looks good! I think there's just a small change needed

[hopeyen]

🙇