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>

samples/wasm-c-api/src/memory.wat

@@ -0,0 +1,11 @@
+(module
+  (memory (export "memory") 2 3)
+
+  (func (export "size") (result i32) (memory.size))
+  (func (export "load") (param i32) (result i32) (i32.load8_s (local.get 0)))
+  (func (export "store") (param i32 i32)
+    (i32.store8 (local.get 0) (local.get 1))
+  )
+
+  (data (i32.const 0x1000) "\01\02\03\04")
+)