WIP: Lines for table layers

[Carifio24]

The goal of this PR is to implement a feature request from Alyssa, which is to have the ability to join points in a table layer with a line. This is done via the add_line functionality from the WWT client (JS-side, this uses WWT's PolyLine annotation).

There are a few outstanding issues:

• This doesn't yet work in the Milky Way mode
• The opacity of the lines is currently always 1. This is due to a WWT bug which was fixed upstream in https://github.com/WorldWideTelescope/wwt-webgl-engine/pull/238 but hasn't yet propagated down to pywwt.
• The lines are added one at a time. This is usually not an issue since it happens quickly, but can become noticeable with a large number of points. If you play the video below at a slower speed (or just scrub to an appropriate frame), this can be seen. I think this is due to the fact that we can only add one line to the annotation at a time. I don't think this is as critical as the opacity, but is something I can look into.

https://user-images.githubusercontent.com/14281631/236512682-ab7e6c2c-6c7f-4f85-ba72-94937a8f9078.mov

[codecov[bot]]

Codecov Report

Patch coverage: 56.00% and project coverage change: -0.47 :warning:

Comparison is base (02379d0) 71.55% compared to head (76f8440) 71.09%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #96 +/- ## ========================================== - Coverage 71.55% 71.09% -0.47% ========================================== Files 18 18 Lines 872 896 +24 ========================================== + Hits 624 637 +13 - Misses 248 259 +11 ``` | [Impacted Files](https://app.codecov.io/gh/glue-viz/glue-wwt/pull/96?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=glue-viz) | Coverage Δ | | |---|---|---| | [glue\_wwt/viewer/table\_layer.py](https://app.codecov.io/gh/glue-viz/glue-wwt/pull/96?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=glue-viz#diff-Z2x1ZV93d3Qvdmlld2VyL3RhYmxlX2xheWVyLnB5) | `74.72% <56.00%> (-2.02%)` | :arrow_down: |

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