finish integration of frontend of backend-step1

finish the event related API except join or leave
finishe interation of frontend and backend-setp2

Done:
Finish join and leave
To-does:
1. Need to add time plugin in event creation
2. 'Open' ->check box
3. Need to support single tag
4. Need to add permission check in event updated API
5. Need hidden the un-owner the edit button
an error in 36node

waiting fix
Fix error for session and sidebar related.
remove node_modules from reposistory
put public/images back to tracked system
add number limit in server api

didn't add in GUI
move some unnecessary files

move the files used before the jam
add number limit in GUI
add permission check in API event/update
to be add pick a date plugin
Finish the time plugin UI

1. add pick time UI plugin in both create and update page
2. Hidden the Open tag, the reason is the open didn't check in API of
server list and participants
3. Add return to home link in each subpage.
forgot to add app.js