ci: enable workspace lint rules

[nyonson]

First patch defines the workspace lint rules and enables them in the root package. While I believe the rules could just be defined in the root package directly, might be nice to share them with the fuzz package (and any future packages)?

Closes #959

[nyonson]

I'll tack on a commit to fix up the lints if cool with this approach.

[trevarj]

Should we bump the rbmt-version commit?

[nyonson]

Yea, let me see how easy it is to update to v0.3.0

[apoelstra]

concept ACK.

Interesting to just turn on use_self completely. In my version of that patch I'd ignored a lot of instances (e.g. for Pkh which is shorter to type than Self). But I noticed Tobin just fixed every instance and that's fine too (and maybe easier to maintain).

The lint is particularly useful here because we have a lot of generics, and Self sets them all while just Miniscript lets the type inference engine set them, which can be confusing for both the reviewer and the compiler.

[tcharding]

Gee wiz, so this is the only thing I was missing. Face palm.

[tcharding]

How about I grab this patch then the ones from #944 sans the re-name and we push that up first? (And I'll include the 'stop using ::*` thing as suggested on that PR.)