canvas dashboards: set max width

[briangregoryholmes]

#5575

Open questions:

• What should the max width be? This PR sets it to 1200px.
• How should the dead space be presented? See below.

[mindspank]

Approved. 1200 looks fine as a width to me and easy to tweak if we'd want different widths.

[mindspank]

@briangregoryholmes @ericpgreen2

Some notes, I don't consider them blockers and we can tweak now that we have the initial stub in place.

• Should we go with 1440 instead?
• Should we scroll the container or the page?
• It looks a bit "dull" but at the same time it wont detract from the analysis. What do you think?

[briangregoryholmes]

Bumped to 1440px and changed the scrolling element to the parent. Colors I'll leave for now, but I agree that it looks quite bland.