remove hard-coded location datasets

[sbfnk]

Following up from https://github.com/Infectious-Disease-Modeling-Hubs/hubUtils/issues/127 and with apologies that I didn't manage to contribute to the discussion at the time. I don't think it's a good idea to have location data sets in {hubUtils} as by taking these on we are taken on the task of maintaining them if e.g. other hubs come into existence with new geographies, country borders or names change etc. I think instead every hub should define its own geographies in a standardised format.

[nickreich]

Noting that this was discussed today at the hubverse dev meeting and we decided that we agree that this should be tackled.