Aladin Skymap blocking load, catalog per-target.

[Fingel]

Describe the bug
Currently the Aladin skymap works by parsing targets that have been directly rendered on the the target list page. While simple, this causes a few issues:

1. Targets need to be rendered on the page before the rest of the script is rendered, potentially increasing load time.
2. There is no way to dynamically update the points on the map, meaning a full page refresh is required.

In particular #2 is problematic if changes to the target table (infinite scroll, filtering, sorting, etc) make it dynamic, as there is no way to update the targets on the Aladin map.

Another issue is that currently an entire Aladin "Catalog" is created per-target. From anecdotal evidence, this means that performance on the map begins to suffer with ~200 targets, becoming basically unusable with a few hundred more than that. The map should be capable of displaying many more targets. Ideally, we would show all targets that match the supplied filters, regardless if they are displayed in the current pagination page or not.