Changed mount point URI decoding in restconf

Changed mount point URI decoding in restconf

- string "yang-ext:mount" in URI means mount point.
  After this string must be string in format moduleName:dataNode
  example:
  /rectconf/config/moduleName1:cont1/cont2/yang-ext:mount/moduleName2:cont3/cont4
     mount point path - moduleName1:cont1/cont2/
     path behind mount point - moduleName2:cont3/cont4

- refactoring of POST, PUT, GET, DELETE tests for status codes
- test for output of several modules to one xml and json file were added

Change-Id: I79bfaec1fab6ffd89295fb8461c167c0c85638ae
Signed-off-by: Martin Sunal <msunal@cisco.com>
Signed-off-by: Jozef Gloncak <jgloncak@cisco.com>