Added bcgov theming and header

[Gavinok]

This resolves the second requirement for #33.

Below are some pictures for reference:

One possible change would be changing the button variant to be an outline. This would better match the buttons seen in org-book.

The current variant more closely replicates the look from the British Columbia Government Design System.

[esune]

It's looking good @Gavinok !

[Gavinok]

With the modified restrictions on the header and logo size