Adds ctrl/cmd+s shortcut to whole application with a noop default

closes #4516
- shortcut for ctrl/cmd+s on application level
- shortens a syntax for any route that is using 'save' method, shortcuts object doesn't have to be defined at all, only the save action.
Merge pull request #4523 from Gargol/issue-4516

Adds ctrl/cmd+s shortcut to whole application with a noop default
Dry up tag saving behavior

Ref #4248
Merge pull request #4610 from novaugust/tag-save-refactor

Dry up tag saving behavior
Sitemaps correctly filter draft posts

fixes #4612

- adds missing line of code to remove draft posts
- adds tests to check drafts aren't added
Merge pull request #4614 from ErisDS/issue-4612

Sitemaps correctly filter draft posts
Update technical details version numvers

They were a bit dated. Nothing else.
Added Highlight to Markdown Help
Merge pull request #4617 from dbalders/markdown

Added Highlight to Markdown Help
Merge branch 'master' of https://github.com/TryGhost/Ghost

Conflicts:
	core/client/routes/settings/general.js
	core/client/routes/settings/users/user.js
	core/client/templates/modals/markdown.hbs