Dont show banner on single calendar event pages

[StevenSawtelle]

Addresses issue #435

Adds a class to body that doesn't show the banner on any calendar/x pages, but still shows it on /calendar. Other options I considered (well, Simon considered let's be real):

• Remove the banner entirely from the page in the <script>
• Add a class to the pp-banner itself that gives it a display: none
• Try and modify the hugo template to not show the banner on single event pages, but this seems like it would require a huge refactor to hugo and I got scared

Calendar page:

Event page:

[ionous]

re:

"Try and modify the hugo template to not show the banner on single event pages, but this seems like it would require a huge refactor to hugo and I got scared"

i logged an issue for making separate hugo pages for things.
i think that'll be a good long term direction. ( and doesn't have to block this issue or this pr )
#790

[ionous]

looking this over again, i think this idea that @StevenSawtelle and i worked out is a decent one.
i think -- because the class addition isn't specific to the pp-promo-banner it might be better to live in events.html -- maybe here:

shift-docs/site/themes/s2b_hugo_theme/layouts/partials/cal/events.html

Line 96 in 87980dc

var params = parseURL();

where there is a (jquery) on ready.
we could probably take this, and then move it later if we wanted.

[carrythebanner]

Thanks @StevenSawtelle!