Fix for providing a highly visible highlighting mechanism for links or controls when they receive keyboard focus. ...

(WCAG 2.0, Additional Techniques (Advisory) for Sucess Criterion 2.4.3, https://www.w3.org/TR/UNDERSTANDING-WCAG20/navigation-mechanisms-focus-order.html)

Changes:

- Added an outline to links, buttons, select menus and other bootstrap form controls.
- The outline colour was set to #107896 (Darkest Alice Blue) which is the default colour for links.
- The default outline with set to 2px, except for buttons where it is set to 3px
to improve visiblity.

Fix for #2170.

Fix for making links have a higher color contrast to other text in blocks. (#2192) ...

The changes were based on the article  https://www.viget.com/articles/color-contrast/

Changes:
 - Link color has been  changed from #337ab7 to #107896.
According to https://webaim.org/resources/linkcontrastchecker/?fcolor=000000&bcolor=FFFFFF&lcolor=107896 (the "Link to Body Text" ratio is 4.14:1 and passes WCAG A test and "Link to Background" ratio is 5.06 and passes the 5.06:1 which satisfies WCAG AA test.)
- The TinyMce editor required new stylesheets to be created.

Fix for issue #1457

refactoring css variables to be more descriptive when re-branding the site

Update order of variable loading

Update asset structure with webpacker gem