refactor: deprecate sp1-helper

[ratankaliani]

Overview

• Deprecate sp1-helper and consolidate logic in sp1-build.
• Add a deprecation warning to sp1-helper with re-exports.
• Refactor the sp1-build crate for usability.

Misc

Note: In several places, SP1's next version is assumed to be 1.2.0. Will need to change this if that's not the case.

sp1/helper/src/lib.rs

Line 2 in 0718ac7

since = "1.2.0",

sp1/book/writing-programs/compiling.md

Lines 53 to 85 in 0718ac7

	## Build Script
	If you want your program crate to be built automatically whenever you build/run your script crate, you can add a `build.rs` file inside of `script/` (at the same level as `Cargo.toml` of your script crate) that utilizes the `sp1-build` crate:
	```rust,noplayground
	{{#include ../../examples/fibonacci/script/build.rs}}
	```
	The path passed in to `build_program` should point to the directory containing the `Cargo.toml` file for your program. Make sure to also add `sp1-build` as a build dependency in `script/Cargo.toml`:
	```toml
	[build-dependencies]
	sp1-build = "1.2.0"
	```
	You will see output like the following from the build script if the program has changed, indicating that the program was rebuilt:
	````
	[fibonacci-script 0.1.0] cargo:rerun-if-changed=../program/src
	[fibonacci-script 0.1.0] cargo:rerun-if-changed=../program/Cargo.toml
	[fibonacci-script 0.1.0] cargo:rerun-if-changed=../program/Cargo.lock
	[fibonacci-script 0.1.0] cargo:warning=fibonacci-program built at 2024-03-02 22:01:26
	[fibonacci-script 0.1.0] [sp1] Compiling fibonacci-program v0.1.0 (/Users/umaroy/Documents/fibonacci/program)
	[fibonacci-script 0.1.0] [sp1] Finished release [optimized] target(s) in 0.15s
	warning: [email protected]: fibonacci-program built at 2024-03-02 22:01:26
	````
	The above output was generated by running `RUST_LOG=info cargo run --release -vv` for the `script` folder of the Fibonacci example.
	### Advanced build options
	To configure the build process when using the `sp1-build` crate, you can pass a [`BuildArgs`](https://docs.rs/sp1-build/1.2.0/sp1_build/struct.BuildArgs.html) struct to to the [`build_program_with_args`](https://docs.rs/sp1-build/1.2.0/sp1_build/fn.build_program_with_args.html) function. The build arguments are the same as the ones available from the `cargo prove build` command.