feat: embedding well known canisters at build time

[NikolaMilosa]

Description

DRE team would highly benefit if we could have a feature like this for well known canisters. Probably others as well. This PR adds a build.rs for dfx-core which creates a file at build time for well known canisters.

Fixes # (issue)

How Has This Been Tested?

This was mostly tested during development with:

./target/debug/dfx --identity default canister --ic call governance list_proposals

# Both following are the same:
./target/debug/dfx canister sign --query rwlgt-iiaaa-aaaaa-aaaaa-cai read --network ic
./target/debug/dfx canister sign --query registry read --network ic

Added two tests to canister sign and canister call scripts

Checklist:

• [x] The title of this PR complies with Conventional Commits.
• [x] I have edited the CHANGELOG accordingly.
• [x] I have made corresponding changes to the documentation.

[NikolaMilosa]

Not sure how I would go about migrations docs for this. Do you have some proposals?