Update Google Component to use Settings file

This removes the need for an additional file and folder in the
“credentials” folder.

Google Calendar ID will now be stored in the “config.properties” file.

Important note! Prior to this version, you should extract your Calendar
ID from “credentials/googlecalendar/ChirpTaskTimedTaskCalendarID.txt”,

Append the following into config.properties :
GOOGLE_CALENDAR_ID=<insert your Calendar ID here>

(without the angular brackets)
Remove unused Calendar object, refactor methods

Refactored “retrieveCalendar” to “initializeCalendar”
Merge branch 'master' of https://github.com/cs2103aug2014-w10-4j/main

Conflicts:
	src/chirptask/common/Settings.java