"Debug symbols" for plutus-tx

### Describe the feature you'd like

Would be great if the compiler produced 2 artifacts, one version of the contract with all debugging code-paths stripped out to be used on-chain and one with debugging kept in for off-chain usage.

This goes beyond `remove-trace` in two ways:

1. Both artifacts are created at once, so there's no need to call with a different set of plugin options
2. User extensible definition of "debugging code path" (described below)

I think there are 2 kinds of cases where we'd want to specify something as a "debug code path" (perhaps telling the compiler this through annotations?)

First is "unconditional", where any time some term appears it is unconditionally replaced with some other term. `trace` gets replaced with `flip const`.

Second is "conditional", where we use some special function to indicate a promise that some subset of the codomain corresponds to failure-case debugging. E.g. `debugFailure (fromBuiltinData d) :: Maybe a` would get rewritten to `(Just . unsafeFromBuiltinData) d :: Maybe a` in prod mode (and `debugFailure` would act as `id` otherwise), and the user is promising that in the `Nothing` case there will just be some tracing followed, ultimately, by a call to `error`.

### Describe alternatives you've considered

Status quo, basically.