Google/calendar list

[Gautime]

Added the functionality to view the list of calendars present on the uesr's profile using simple command /calendar list. User will be able to see list of all the calendars on their profile. Along with that list, there will appear buttons with each calendar in the list. Users can click on one of those buttons and select the calendar they want to create, update, delete, read events from or to that calendar. Screenshot is attached for reference. Button will appear for all calendars except the one which is already selected ad being worked with.

Also the login and logout links are converted to a single button. Logout button example is attached in the screenshot.

[CLAassistant]

All committers have signed the CLA.