Rename "Source" to "Collection Type"

docs/architecture.md

...d/chn_spreadsheet/example_spreadsheet_channel_config.json

...hid/chn_spreadsheet/migrations/0014_auto_20191216_1054.py

internewshid/chn_spreadsheet/tests/kobo_master_tests.py

...spreadsheet/tests/test_files/master_kobo_single_item.xlsx

.../chn_spreadsheet/tests/test_files/sample_kobo_master.xlsx

...hid/data_layer/migrations/0020_message_collection_type.py

...rnewshid/data_layer/migrations/0021_auto_20191216_1007.py

...wshid/data_layer/migrations/0022_remove_message_source.py

internewshid/data_layer/models.py

internewshid/data_layer/tests/factories.py

internewshid/hid/apps.py

internewshid/hid/filters.py

internewshid/hid/fixtures/bangladesh-refugee-crisis.json

internewshid/hid/fixtures/sudan.json

internewshid/hid/forms/item.py

internewshid/hid/forms/upload.py

internewshid/hid/migrations/0005_initial_tabbed_page.py

internewshid/hid/tables.py

internewshid/hid/tabs/view_and_edit_table.py