Core 901 add portal routing handler

[RoyEJohnson]

CORE-901

[TomWoodward]

what is here looks mostly good. i am a little concerned about the click handler changing the url, and wouldn't that produce an error with the urls that you're manually including the portal prefix on?

this doesn't seem to address the entire issue, especially the part about loading the flex page definition based on the portal name and using the layout config from the flex page (that is what makes it "portaly" when the flex page uses the landing page layout)

it would also be fine to merge this and then do the layout thing in a separate pr if you want

[TomWoodward]

i'm wondering if there are any of these, like k12, blog, general, that we explicitly don't want to work in the portal. i guess probably they're not hurting anything by being in there

[RoyEJohnson]

I was unable to see that this did anything.

[RoyEJohnson]

I have changed the link handling: I created a rewriteLinks utility in the PortalContext that rewrites the href of any links in a given element to add the portal if portal is set.
The footer element calls it, and so does the raw-html component, which is used in the adoption and interest form headers.I directly rewrote links in a few other pages.
I updated DefaultLayout to use a landing page layout when the portal is set.
It assumes a flex page with a landing page layout is a portal, but also any path that has a portal and something that loads successfully will be treated as a portal.
So these are all portal pages:
http://localhost:3000/b2s-fall-24
http://localhost:3000/b2s-fall-24/details/books/biology-2e
http://localhost:3000/b2s-fall-24/careers
http://localhost:3000/not-a-page/careers

We might want to verify that the portal corresponds to an existing flex page before setting it?