tizenrt: Add release defconfig from docker image

Before updating TizenRT in build script,
I thought I would be better to maintain config files in sources' dir.

File "config/tizenrt/release/artik05x/configs/defconfig"
is coming from "tizenrt_release_config" in travis build container:

https://hub.docker.com/r/iotjs/ubuntu/

(I don't know if this file is tracked elsewhere ?)

Debug config has just been renamed, and script path adjusted.

Note for later, it would make sense to align both after upgrade.

Relate-to: jerryscript-project#1780
Credit-to: iotjs <https://hub.docker.com/u/iotjs/>
IoT.js-DCO-1.0-Signed-off-by: Philippe Coval p.coval@samsung.com