Added new view in 'My Page' dashboard, for account settings

Only routes and view are implemented. The contents has no function.
Added Account Settings link to Username dropdown.
Revised naming for routes to settings page.

Non functional change to extended the cantas base view.
Avoided using settings.js as a name for other files.

settings.js, as a name, should belong to the first file in root dir.
So, settings for user account should have relevant files more aptly named.
Refactored naming for account settings.

No functional changes.
'settings' is too generic a word to refer to Account Settings,
so any naming was amended to specifically refer to 'account' settings.
Add Demo site to README.