[wrt]update test suite.json add test app

Impacted TCs num(approved): New 0, update 3 suite name
Unit test platform: [tizen]
UT result: Pass 3, Fail 0
Merge pull request #978 from linshen/shenlin/updatedigital-tizen

[wrt]update test suite.json add test app
[webapi-usecase] add usecase README file for description

- Add 18 usecase README.md to describe basic funtionalities and covering methods
Merge remote-tracking branch 'upstream/master'