(ui): add reader/writer path in preferences
Description
For many applications, we need to often load/save some data in the same folder. For the testing it should also be simpler to set all the required data in a folder (set in the preference) and define the filename in the XML.
Proposal
Add path to the preferences to save/load data
- update IReader/IWriter to defined preferences folder on tag
- update IReader
hasLocationDefined
to return false if the file does not exist - add readers/writers in the activity xml to automatically load/save the data