describe_data: Return a sentence describing the given data
In niedermansam/marketR: Utilities for Automating Marketing Reports

Return a sentence describing the given data

1 2	describe_data(data, dimension, metric, subject = "users", action = "made up", label = "%", object = "of total traffic")

`data`	A dataframe to summarize.
`dimension`	The dimension (or grouping variable).
`metric`	The data to summarize.
`subject`	The subject of the sentence (e.g. users, pageviews, etc.)
`action`	The action of the subject (e.g. made up, spent, etc.)
`label`	The label for the metric (e.g. %, minutes, etc.)
`object`	Noun phrase to include in predicate (e.g. "of total traffic", "of all users", etc.)