All services: Adding new page template and new utilities

[Garneauma]

• Adding All services page template
• Adding bg-light utility class to add light-grey background
• Adding nav-links utility class to style list of navigational links
• Adding padding and margin utility classes

Changes related to WET-498

[duboisp]

Incomplete review, just some early comments.

[Garneauma]

Pre-approved upon successful review and application of all requested changes.

[duboisp]

I review and a few change is required, see inline comments.

I only checked the pattern, some fix need to be replicated across the other theme and in French too. I didn't identified all instance. I will check that in a subsequent review.

Note: I carefully reviewed the CSS generated for the padding + margin and it looks good. May be eventually, we should look on providing a working example that show may be not all possibility but at least each aspect of the applied style.

There is a lot of addition in this PR, we will need to be careful to list all of them in our release note. @ouafaaetta head-up

[duboisp]

See my inline comments, still a few edits. Some are more related to content.

[duboisp]

Reviewed and tested everything.

Just one thing left and then we will be good to merge.

This is a minor change with all the new utilities added

This is a patch change for the template addition because it is limited to one single page.