Implement most missing wasm-c-api APIs (#303) (#676)

Remove unnecessary functions and implement more APIs:
- wasm_##name##same
- wasm##name##as_ref
- wasm_ref_as##name##
- wasm_ref_delete
- wasm_module_validate
- wasm_table_get/set/size
- wasm_memory_size
- wasm_config_new
- wasm_foreign_new

And add more wasm-c-api samples, update the related documen, add more CI rules.

Signed-off-by: Wenyong Huang <wenyong.huang@intel.com>

core/iwasm/interpreter/wasm_loader.c

@@ -7881,7 +7881,7 @@ fail_data_cnt_sec_require:
 #if WASM_ENABLE_REF_TYPES != 0
                 case WASM_OP_TABLE_INIT:
                 {
-                    uint8 seg_ref_type, tbl_ref_type;
+                    uint8 seg_ref_type = 0, tbl_ref_type = 0;
 
                     if (!wasm_get_ref_types_flag()) {
                         goto unsupported_opcode;