Avoid using random DOM ids

[mayel]

The random_dom_id/1 helper function (which generates a string like random-68436) is used quite a few places as a way to avoid errors like #1080, since both live components and DOM elements that have a LV JS hook need to have unique DOM IDs, but it probably messes with LV's change tracking / diffing, so better approaches are needed.

[mayel]

So far we've tried things like id={"media_link-#{@showing_within}-#{id(@media) || random_dom_id()}-via-#{@parent_id}"} but it gets messy and sometimes breaks (like when the page layout changes and an element is shown in multiples places in some new way) and we end up with non-unique ones