Description of change

Now finds the package and binary target for local runs and deployments by looking in the target's source file for a #[shuttle_runtime::main string. (no ] so that #[shuttle_runtime::main(...)] can be found)
Also passes --bin to cargo build and binary_name to deployment args.

✔️ Gets rid of the requirement that the target (binary) name of the Shuttle service has to match the crate name :)
✔️ Sets us up to add -p/--package and --bin args to build/run/deploy commands.

⚠️ Breaking change for users who do

use shuttle_runtime::main;

#[main]
...

How has this been tested? (if applicable)

Intergration tests were added and adjusted for the changes, and local run and deploy was manually tested (works the same way).