[Task]: Tour of Beam URLs

[alexeyinkin]

What needs to happen?

Currently ToB shows /tour/<sdk> as the URL for all units. These need to match the current unit's ancestor's chain of IDs like /tour/java/module-id/group-id/group-id/unit-id.

Also we need to show a unit when its URL is typed in.

For a module or a group URL, we must show its first unit and update the URL with that unit's URL.

Issue Priority

Priority: 3

Issue Component

Component: beam-playground

[nausharipov]

.take-issue