SDAP-401: Added JSON output formatting for COVERAGE plotting

[RKuttruff]

Added output formatter for COVERAGE plotting to be used by the /match_spark endpoint.

Outputs support the following plots:

• Time series (primary + secondary vs time)
• Scatter (primary vs secondary)
• Primary histogram
• Secondary histogram
• Primary histogram time series
• Secondary histogram time series
• Difference map (primary - secondary)

To use this formatter, set parameter output=CAML

Parameters:

Parameter	Description
camlPrimary	Required: Variable name from the primary dataset that is being plotted.
camlSecondary	Required: Variable name from the secondary dataset that is being plotted. Note that this will override the parameter parameter.
camlChartTypes	Comma-separated list of plot types to output. Default: Scatter, histograms, difference map. Values: time_series: Time series plot scatter: Scatter plot histogram_primary: Primary histogram histogram_secondary: Secondary histogram histogram_primary_timeseries: Primary histogram time series histogram_secondary_timeseries: Secondary histogram time series trajectory: Difference map
camlHistBins	Comma-separated list of bins for histogram plots.