Enhance the --location flag for the "create event" command

Currently, the createevent command includes a --test-location flag that accepts a comma separated list of arguments.

There are two goals with this ticket:

1. Improve the location option so that it accepts different types of location types (see https://docs.microsoft.com/en-us/graph/api/resources/location?view=graph-rest-1.0)

One suggestion is to split the comma separated list of arguments into separate flags.

Original discussion here: https://github.com/mattermost/mattermost-plugin-mscalendar/pull/19#discussion_r360923881

2. Implement some form of intelligent completion so the user isn’t required to fill out 6 parameters on the CLI

see: https://github.com/mattermost/mattermost-plugin-mscalendar/pull/19#discussion_r360711618