Improve installation page to simplify and direct users to installation method

[DragaDoncila]

I mean that to very few people reading this page are the two options of equal value.
So to me it makes more sense to be opinionated and pick one route -- the Python one right now -- and then provide the other route -- the bundle/app right now -- as the clear alternative.

Having two tiles like that makes sense on the homepage or in on a quick-start page or some other page where other content will continue (so the tiles are the "go install, here's two options, come back when done"). But this is already the installation page that the user actively selected, so I think having a tile that does nothing is just weird. In general I think sometimes we try to present too many options at once, each as equivalent, rather than a clear main way, with perhaps an alternative.

(I love the admonitions because I love color. In Caldeum color means wealth!)

Originally posted by @psobolewskiPhD in #958 (comment)

[DragaDoncila]

From #958 (comment) :

In my world we would have the python install instructions and the app install instructions.
Homepage has a card/tab/tile/whatever for each.
And each of them would have an admonition pointing to the other one near/at the top.