Create chain agnostic structure

[salieflewis]

Dreamweaver should be extensible such that it works on any chain a database contract is deployed to, that means that chain configuration should take place in a .env file.

I'm surely forgetting some, but here are a couple areas where this needs to be implemented.

1. viem/client.ts
2. bundlr/bundlrActions.ts (apiUrl)
3. fetch/utils/getLastBlockNum.ts

[0xTranqui]

add this file to the list (you can see it hardcoding what blockexplorer to use) https://github.com/public-assembly/dreamweaver/blob/jawn/fluff-removal/fetch/utils/getLastBlockNum.ts