Add user-defined category-label colors (#1402)

* Add user-defined category-label colors

Fixes https://github.com/chanzuckerberg/cellxgene/issues/1152

As described in https://github.com/chanzuckerberg/cellxgene/issues/1307

* Respond to feedback from @bkmartinjr in nodejs

* Respond to feedback from @bkmartinjr in python

* Add tests to the server module

* Autoformat python, run linter

* Make colors_get error handling specific

* Respond to feedback from @bkmartinjr

* Respond to feedback from @bkmartinjr

* Fix whitespace

* Fix python lint errrors

* Update documentation

* Add --disable-user-colors option to launch and cxgtool.py

* Fix python formatting

* Rename '--disable-user-colors' to '--disable-custom-colors'

server/data_anndata/anndata_adaptor.py

@@ -12,6 +12,7 @@ from server_timing import Timing as ServerTiming
 from server.data_common.data_adaptor import DataAdaptor
 from server.data_common.fbs.matrix import encode_matrix_fbs
 from server.common.utils import series_to_schema
+from server.common.colors import convert_anndata_category_colors_to_cxg_category_colors
 from server.common.constants import Axis, MAX_LAYOUTS
 from server.common.errors import PrepareError, DatasetAccessError, FilterError
 from server.compute.scanpy import scanpy_umap
@@ -333,6 +334,9 @@ class AnndataAdaptor(DataAdaptor):
             lfc_cutoff = self.config.diffexp__lfc_cutoff
         return diffexp_generic.diffexp_ttest(self, maskA, maskB, top_n, lfc_cutoff)
 
+    def get_colors(self):
+        return convert_anndata_category_colors_to_cxg_category_colors(self.data)
+
     def get_X_array(self, obs_mask=None, var_mask=None):
         if obs_mask is None:
             obs_mask = slice(None)