Tree growth visualization

[pangtao22]

Features added to visualizer:

• histogram of 4 distance metrics
• When sliding through tree growth, the subgoal is shown, and connected to the best 10 candidate nodes in the tree by dashed lines colored by the distance computed from the selected distance metric.
• subgoal visualization in meshcat
• dropdown menu for different aspect ratios.

Some changes are made to IrsRrt.calc_metric_batch to support computing distances using different metrics while building the tree and after the tree is built. As a result, IrsRrtGlobal is removed as its only purpose is to support a different distance metric. Per f2f discussion with @hjsuh94, distance metric is now a param in IrsRrtParams and all different metrics are handled by IrsRrt.calc_metric_batch. @lujieyang This will require some changes on your Allegro hand branch, but it should accommodate the new quaternion distances you just wrote?

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This change is 

[lujieyang]

I feel we have two versions of implementing different modes for cal_metric_batch: 1) using if statement 2) inherit for subclass. I think quaternion mode can fit in both.