winch: Introduce winch-environ (#6017)

This commit introduces the `winch-environ` crate. This crate's responsibility is
to provide a shared implementatation of the `winch_codegen::FuncEnv` trait,
which is Winch's function compilation environment, used to resolve module and
runtime specific information needed by the code generation, such as resolving
all the details about a callee in a WebAssembly module, or resolving specific
information from the `VMContext`.

As of this change, the implementation only includes the necessary pieces to
resolve a function callee in a WebAssembly module. The idea is to evolve the
`winch_codegen::FuncEnv` trait as we evolve Winch's code generation.

winch/environ/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+authors = ["The Winch Project Developers"]
+name = "winch-environ"
+description = "Implementation of Winch's function compilation environment"
+license = "Apache-2.0 WITH LLVM-exception"
+repository = "https://github.com/bytecodealliance/wasmtime"
+version = "0.6.0"
+edition.workspace = true
+
+
+[dependencies]
+winch-codegen = { workspace = true }
+wasmtime-environ = { workspace = true }
+wasmparser = { workspace = true }