cli: Add arch option to use build-sbf or build-bpf

[joncinque]

Problem

Some programs use cargo build-sbf, like the solana-program-library, but the verifiable builds through Anchor default to cargo build-bpf. I noticed this while performing a verifiable build of token-2022.

Solution

This adds an --arch flag to control using build-sbf if you pass in --arch sbf, defaults to bpf. This way, it'll be possible to support SBFv2 and any other format that might come out. I initially had this as a simple bool flag, but the arch flag makes more sense to me. Let me know what you think!

[vercel]

@joncinque is attempting to deploy a commit to the coral-xyz Team on Vercel.

A member of the Team first needs to authorize it.

[0xdeepmehta]

lgtm 🚀

[Henry-E]

Sounds good. In the future we should probably switch to sbf as the default option but probably best to leave it as bpf for now in the next anchor version.

Usage is anchor test --arch sbf or anchor build --arch sbf.