Integrate `mapclassify`

From the [geopandas.plot docstring](https://geopandas.org/en/stable/docs/reference/api/geopandas.GeoDataFrame.plot.html#geopandas.GeoDataFrame.plot)

> Name of a choropleth classification scheme (requires mapclassify). A mapclassify.MapClassifier object will be used under the hood. Supported are all schemes provided by mapclassify (e.g. ‘BoxPlot’, ‘EqualInterval’, ‘FisherJenks’, ‘FisherJenksSampled’, ‘HeadTailBreaks’, ‘JenksCaspall’, ‘JenksCaspallForced’, ‘JenksCaspallSampled’, ‘MaxP’, ‘MaximumBreaks’, ‘NaturalBreaks’, ‘Quantiles’, ‘Percentiles’, ‘StdMean’, ‘UserDefined’). Arguments can be passed in classification_kwds.

Start with the GeoDataFrame.plot docstring linked in the issue and review the current plotting entry point for how classification is handled. Done means integrating mapclassify so the listed schemes and classification_kwds are supported as described; no specific source file or test is named.

Written by the indexing model from the issue text.