feature: print useful error message upon wit_version mismatch

[nick1udwig]

Is your feature request related to a problem? Please describe.
When I forget to add a "wit_version" to my metadata.json I get this error:

ERROR src/main.rs:896: 
   0: Command `wasm-tools ["component", "wit", "/home/nick/git/kit/foo_bar/test/foo_bar_test/foo_bar_test/target/wit", "-o", "/home/nick/git/kit/foo_bar/test/foo_bar_test/foo_bar_test/target/bindings/foo_bar_test/target.wasm", "--wasm"]` failed with exit code 1
      stdout: 
      stderr: error: failed to resolve directory while parsing WIT for path [/home/nick/git/kit/foo_bar/test/foo_bar_test/foo_bar_test/target/wit]

      Caused by:
          0: failed to parse package: /home/nick/git/kit/foo_bar/test/foo_bar_test/foo_bar_test/target/wit
          1: interface or world `process-v0` not found in package
                  --> /home/nick/git/kit/foo_bar/test/foo_bar_test/foo_bar_test/target/wit/tester:sys-v0.wit:26:13
                   |
                26 |     include process-v0;
                   |             ^---------
   0: 

Location:
   src/build/mod.rs:51

  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ SPANTRACE ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

   0: kit::build::run_command
      at src/build/mod.rs:42
   1: kit::build::compile_rust_wasm_process
      at src/build/mod.rs:239
   2: kit::build::compile_package_item
      at src/build/mod.rs:460

Describe the solution you'd like
Ideally we should print a USEFUL error message for the user.