Add Sn prefix to project names in all places

[THenry14]

Follow-up of #958 and a sibling issue to #998

Our project binaries use sn prefixes in all places, but usages of names with and without prefixes in other places are inconsistent.

E.g.

starknet-foundry/crates/cast/src/main.rs

Line 21 in e0bdc7c

#[command(about = "Cast - a Starknet Foundry CLI", long_about = None)]

or in docs headings

We should consider if we want to use consistent names in all places.