[6.0][mediacontroller] add MediaControllerPlaylists interface

[6.0][mediacontroller] add MediaControllerPlaylists interface

[acr]
http://suprem.sec.samsung.net/jira/browse/TWDAPI-247

[description]
>> refactor_04 <<
add MediaControllerPlaylists interface to MediaControllerServer.
Methods added to MediaControllerPlaylists interface:
+ createPlaylist
+ savePlaylist
+ deletePlaylist
+ getAllPlaylists

[verification]
tested manually in chrome console
tct-mediacontroller-tizen-tests fails with 2 TC:
- MediaControllerServer_iconURI_attribute.html <- has to be modified,
  because attribute iconURI is no longer readonly
- MediaControllerServerInfo_iconURI_attribute.html <- has to be modified,
  because attribute iconURI is no longer readonly

Change-Id: I4cd792eb6e87f1803bd3e56b54accc91f1e0fd8d
Signed-off-by: Dawid Juszczak <d.juszczak@samsung.com>