Allow to invoke the quick call entry wasm_runtime_quick_invoke_c_api_import to
call the wasm-c-api import functions to speedup the calling process, which reduces
the data copying.
Use `wamrc --invoke-c-api-import` to generate the optimized AOT code, and set
`jit_options->quick_invoke_c_api_import` true in wasm_engine_new when LLVM JIT
is enabled.
Add APIs to help prepare the imports for the wasm-c-api `wasm_instance_new`:
- wasm_importtype_is_linked
- wasm_runtime_is_import_func_linked
- wasm_runtime_is_import_global_linked
- wasm_extern_new_empty
For wasm-c-api, developer may use `wasm_module_imports` to get the import
types info, check whether an import func/global is linked with the above API,
and ignore the linking of an import func/global with `wasm_extern_new_empty`.
Sample `wasm-c-api-import` is added and document is updated.
