Vectorizing Indicators

[hoxbro]

This PR does the following:

• Implementing the new vectorized VSpans and VLines and removing the previous workarounds for it.
• Restructuring how Indicators are called by merging region_df and field_df before passing it into an Indicator.
• Move hover creation to indicators.
• Update the minimum Python version to 3.9 as it is needed for Bokeh 3.2.
• Always have the merged dataframe have the same column and type.
• Move get_indices_by_position into Annotation Table.
• Add basic implementation of point detection.