move <noscript> from <head> into <body>

The <noscript> element is not allowed to contain an <h1> tag when it is in <head>. This was causing W3C validation to hard fail for every page, masking further validation errors.

Also add proper a11y, i18n, capitalization to the message.

See: http://www.w3.org/TR/html5/scripting-1.html#the-noscript-element

Test plan:

 - Disable JavaScript
 - Ensure the "You need to have JavaScript enabled..." message appears.
 - Run W3C HTML Validator on a Canvas page
 - Check that there are no errors referring to <noscript> or <h1> tags
   in the <head>

Change-Id: I2904b5ecdff11cd4722d3fee173c5ff1dedf0063
Reviewed-on: https://gerrit.instructure.com/38807
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Liz Abinante <labinante@instructure.com>
Product-Review: Adam Phillipps <adam@instructure.com>
QA-Review: Adam Phillipps <adam@instructure.com>