Reinstate meta viewport width & initial scale

Allows devices to use responsive layouts
Fix typo
Clarify that other distrinbuted version control systems exist

In particular make the claim specific to distributed version control
systems, rather than specific to the tool Git.
Remove duplcate panels.scss import
Stop assets from caching
Updates to analytics tools guidance following Gareth's input
Responsive layout updates for role index pages
cite open standards principles, not the consultation
more explanation of exit costs
link to CESG
bullet list for open source Further reading
spelling mistake
more clarity around use of open standards to mitigate lockin
Align breadcrumb keyline with edge of page
[jc] Removed gramatically incorrect apostrophe
Fix broken link to Git
Add a suggested CONTRIBUTING.md file
Add line about proofreading and amends

Remove punctuation from end of bullet points as per the styleguide
Remove repetition, fix typo
Removed superfluous audience