Allow entered text to be used as a tag

In user research a common problem with tagging was discovered. Users
would enter text into the input field then click away or on the submit
button. The default behaviour would hide the tag drop down and lear the
tag input. So forms were being submitted without the intended tags.

* Use the select2 option “selectOnBlur” to turn user input into a tag
on blur
Make bulk edit options clearer

* White checkboxes on white backgrounds are easily missed
* Bring attention to the checkboxes by darkening the background
Give checkbox column a header

* Label checkboxes with “Edit”, and include a tooltip about how to use
bulk editing tools
* Automatically start all tooltips and remove an old inline script
Tooltip if hovering on disabled bulk edit buttons

* Users often try to interact with the disabled bulk edit buttons
* Include a tooltip when hovering on the buttons whilst they are
disabled, with an explanation of how to use the buttons
* When a selection has been made the tooltip won’t show
Remove selectable table script call in style guide

* We don’t instantiate like this any more
Include a border on the edit mapping header
Add mousetrap for keyboard shortcuts
Create a go to mapping modal

* When pressing “g m” a modal appears asking for an old URL, entering
the URL will take you directly to that mappings edit screen
* “g m” for “go to mapping”
* Uses the existing find_global method to resolve a mapping without site
Fix failing hits test

* There were two “Old URL” fields and the assertion was looking at the
wrong one
* Instead look for “Old URLs”
Merge pull request #251 from alphagov/tagging-usability-tweak

Allow entered text to be used as a tag
Merge pull request #253 from alphagov/go-to-pages

Create a go to mapping modal
Allow filtering of organisation list

In user research it was noted that finding organisations in the list
has become difficult, it’s grown quite long. This filter helps find
organisations quickly.

* Hide table rows that don’t match the input
* JavaScript only, the field is hidden when JS is disabled
* Prevent sideways shifting when page length changes and scrollbars
hide/show
Remove rogue </p> tag
Merge pull request #252 from alphagov/edit-mapping-tip

Highlight bulk edit tools and include guidance
Merge pull request #250 from alphagov/filter-orgs-list

Allow filtering of organisation list
URLs must contain at least one "."

We started prepending http:// to the start of URL values so the user
didn’t have to. This left a hole in our validation where “something”
would become “http://something” and pass validation checks.

* Check host contains at least one period, mostly to prevent accidents
Merge pull request #256 from alphagov/new-urls-must-contain-a-dot

URL hosts must contain at least one "."
Inform users of entire site redirects or archives

- This is to avoid users getting confused by a site having zero
  mappings, or trying to add mappings for globally redirected or
  archived sites.
- There are two new sites database table columns of type boolean -
  `global_archive` and `global_redirect`. False = not
  redirected/archived and True = redirected/archived.