dfx should have the ability to set controller per the public spec

[p-shahi]

• usage message reviewed
• update CLI reference Add set-controller to doc docs#232
• agent pr feat: add set controller to the management canister agent-rs#51

[nomeata]

Right now you can do

dfx canister ic:00 call set_controller '({canister_id = "ic:…", new_controller = "ic:…"})`

right?

I expect the management canister to grow a lot over time (see, for example, https://github.com/dfinity-lab/ic-ref/pull/120), and it might not only save us lot of work to just let users use it directly, but be actually easier for users, because they only learn about that interface and can immedially use these features from the command line, JS, Motoko, Rust…

Maybe the missing piece is that when parsing a principal in candid, you also want to support the local canister aliases?