chore: add cleanup for bb installation

[kobyhallx]

Adds cleanup for acvm-backend-barretenberg when performing new installation.

[TomAFrench]

I don't think this should be merged in its current form for a couple of reasons:

• This PR currently nukes the entire backend directory including the CRS so users will have to redownload it from scratch. This unnecessarily slows down the UX as the CRS can be shared between bb versions.
• The suggested changes to fix: Download expected bb version if installed backend has version mismatch noir#3150 remove the need for this PR when updating to future versions of nargo.
• It's generally "abstraction leaky", there's no reason for noirup to be aware of backends.

[kobyhallx]

I think its generally a good practive to clean particular backend before installing new one. Your current artifacts may be broken or out dated and cleanup would help with this.