Web: Changing UI to have dropdowns for actions

* Adding dropdowns for actions
* Adding custom CSS for dropdown to alter width
* Adding event handler onEditPost to handle event handler for Edit Post

TO DO : Add modal where user can edit the Post title, URL, if possible
Group
Adding Edit option for a Post

* UI : Modified home controller to handle edit option
* UI : revamping Add post to enable reuse of code for Edit option
* Py : taking "id" field property input for post obj
* Py : changing mongo operation to UPDATE instead of Save
Merge branch 'dev'