Some rework for renderableTrailTrajectory (#3742)

Removed feature sweepChunk.
The feature was implemented for version 0.19.0 as an iterative way to calculate renderableTrailTrajectory.
However, due to the function not being active by default, and due multithreading being on the horizon for SPICE2, this code is now removed.

- Removed SweepChunk feature
- Added toggle for Accurate Trail Points (in asset: AccurateTrail)
- Changed min number of accurate points from 0 to 2
- Removed max vertices ceiling
- Fixed issue where number of vertices were not calculated properly
- Fixed point size rendering issue for RenderableTrail
- Changed start/end time for voyager 1 & 2
- Updated description for SampleInterval and TimeStampSubsampleFactor to be more clear
- Moved full sweep pass from update function to new updateBuffer function
- Fixed trail rendering issue when time is exact same as start time of a trail

modules/base/rendering/renderabletrail.cpp

@@ -101,7 +101,7 @@ namespace {
         "Line Fade Amount",
         "The amount of the trail that should be faded. If the value is 0 then the "
         "trail will have no fading applied. A value of 0.6 will result in a trail "
-        "where 60% of the extent of the trail will have fading applied to it. In other"
+        "where 60% of the extent of the trail will have fading applied to it. In other "
         "words, the 40% closest to the head of the trail will be solid and the rest "
         "will fade until completely transparent at the end of the trail. A value of 1 "
         "will result in a trail that starts fading immediately, becoming fully "