Improve new time_ranges property python api & add snippet for time series view, explaining all its options

[Wumpf]

What

Improve VisibleTimeRange python api and add a snippet for time series view which is the primary (but not sole!) user of this feature.

# Create a TimeSeries View
blueprint = rrb.Blueprint(
    rrb.TimeSeriesView(
        origin="/trig",
        # Set a custom Y axis.
        axis_y=rrb.ScalarAxis(range=(-1.0, 1.0), lock_range_during_zoom=True),
        # Configure the legend.
        plot_legend=rrb.PlotLegend(visible=False),
        # Set time different time ranges for different timelines.
        time_ranges=[
            # Sliding window depending on the time cursor for the first timeline.
            rrb.VisibleTimeRange(
                "timeline0",
                start=rrb.TimeRangeBoundary.cursor_relative(-100),
                end=rrb.TimeRangeBoundary.cursor_relative(),
            ),
            # Time range from some point to the end of the timeline for the second timeline.
            rrb.VisibleTimeRange(
                "timeline1",
                start=rrb.TimeRangeBoundary.absolute(300),
                end=rrb.TimeRangeBoundary.infinite(),
            ),
        ],
    )
)

TODO:

• update usage on checklist test!
• integrate with snippet reorg pr
• put the snippet on to timeseries view
• check again whether we can't make TimeRangeBoundary a union and if we can't or don't want note it down into the fbs file why

* think about how to document time range on other places and how to document usage of VisibleTimeRange type itself
* consider providing several snippets
* update docs on visible time range in the manual with some code examples while we're on it?

Checklist

• I have read and agree to Contributor Guide and the Code of Conduct
• I've included a screenshot or gif (if applicable)
• I have tested the web demo (if applicable):
  • Using examples from latest main build: rerun.io/viewer
  • Using full set of examples from nightly build: rerun.io/viewer
• The PR title and labels are set such as to maximize their usefulness for the next release's CHANGELOG
• If applicable, add a new check to the release checklist!

• PR Build Summary
• Recent benchmark results
• Wasm size tracking

To run all checks from main, comment on the PR with @rerun-bot full-check.

[github-actions]

Deployed docs

Commit	Link
a1d40e3	https://landing-4o66jbw9b-rerun.vercel.app/docs

[jleibs]

😅 so much work to get here, but this is awesome!