Implement more wasm-c-apis and enable Envoy integration (#622)

Implement more wasm-c-api APIs to support Envoy integration:
- sync up with latest c-api definition
- change CMakeLists to export necessary headers and install the static library of iwasm
- enable to export tables and memories
- support memorytype and tabletype APIs
- update wasm-c-api sampels
- enable to export importtype APIs

And refine bazel scripts for sample XNNPACK workload, add license headers for sample simple.

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

samples/simple/src/iwasm_main.c

@@ -1,3 +1,7 @@
+/*
+ * Copyright (C) 2019 Intel Corporation.  All rights reserved.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ */
 
 #ifndef CONNECTION_UART
 #include <netdb.h>

samples/simple/src/main.c

@@ -1,3 +1,8 @@
+/*
+ * Copyright (C) 2019 Intel Corporation.  All rights reserved.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ */
+
 extern void iwasm_main();
 int main(int argc, char *argv[])
 {