create csv or some standard data format for the lookup data (Lookup.Java)

**Is your feature request related to a problem? Please describe.**
It would be easier when new date could be added  by person who does not know java. 

**Describe the solution you'd like**
csv or json data structure would be used to store lookup dates. Not [LookUp.java](../blob/master/src/main/java/np/com/bahadur/converter/date/nepali/Lookup.java)



