getContexts(/* mPropertyBag */) {
			return Promise.reject("getContexts is not implemented");
		}
Interface to retrieve the variant management context information.
The context information is a JSON object that has boolean property 'lasthitreached'
indicating that the result is paginated and whether there are more contexts that can be fetched from the backend.
The context information also has JSON object 'types' which has a string property 'type' denoting the type of context (e.g. 'ROLE')
and an array property 'values' containing the id and description of each context.

@param {object} mPropertyBag Property bag
@param {sap.ui.fl.Layer} mPropertyBag.layer Layer
@param {string} mPropertyBag.type Type of context, currently only 'role' is supported
@param {string} [mPropertyBag.$skip] Offset for paginated request
@param {string} [mPropertyBag.$filter] Filters full raw data
@param {string} [mPropertyBag.url] Configured url for the connector
@returns {Promise<object>} Promise resolves as soon as context has been retrieved