Expand functionality of data uploader script to upload both Turtle and JSONLD files in directory

[alyssadai]

We are starting to create + think about vocabulary graph files which are much more easily expressed in a .ttl file than .jsonld (e.g., #182), but nonetheless need to have a way to be easily added to a graph.

Currently, add_data_to_graph.sh only uploads .jsonld files in a directory. To make it easy for a deploying user to upload all data that needs to be in the graph in one go, we could add another loop to the script that performs the same POST request on any .ttl files in the specified directory.

api/add_data_to_graph.sh

Lines 146 to 150 in b65a242

	for db in ${jsonld_dir}/*.jsonld; do
	curl -u "${user}:${password}" -i -X POST http://${graph_url}/${graph_db} \
	-H "Content-Type: application/ld+json" \
	--data-binary @${db}
	done

This script would then work on both directories with just one kind of file (.ttl or .jsonld) or those with a mix of both - allowing us flexibility if we want to recommend storing all vocab-related files separately but still be able to merge them into the graph using the same script.