Implements wasm_builder built-in service

Implements wasm_builder built-in service

1. wasm_builder finds .wasm files based on given WebApp and call
   compileWasmForCaching.
2. compileWasmForCaching creates a cache file(compressed machine code).
3. If the cache is created succesfully, you may find the cache
   file, for example, as below. (Aware that this is one-line!)
   /home/owner/.cache/Apps/WebAppsCache/IBcZLx54d2.WasmCoITest
   /034bf102392fb62cb3d8c4bb4118cbed7df7731c.wasm_cache

Change-Id: I73247f28ef405068f6dd45005312b06621f67f2a
Signed-off-by: DongHyun Song <dh81.song@samsung.com>
Signed-off-by: Juhyun Choi <honest.choi@samsung.com>