Devnet Container Specializations (DONT MERGE)

[enobayram]

This PR contains a variant of the block-explorer that's specialized for the needs of the devnet container. It's not meant to be merged. Ideally, these differences would be expressed in code and the behavior would be chosen at runtime based on the configuration, however, Obelisk makes it extremely hard to do that, because:

• The types and the abstractions used for defining the routing logic use very advanced type system features, so they are very rigid against abstraction. It's much harder than it seems to abstract the code over whether an /explorer/ prefix exists in the route.
• It's not possible to access the configuration in the routing logic. Even using unsafeXYZ it would still be very hard since Obelisk doesn't expose the necessary logic.
• Even if we used some sort of compile time constant to chose the behavior, we'd have to plumb that flag all the way through obelisk's Nix layers.

In light of these difficulties, we've decided to keep the differences in this branch for the time being.