Add import script for NHS England CCG areas

[chris48s]

As with the Police Force boundaries (see pull request #73), NHS CCG boundaries for England are available as open data, but they aren't formatted in such a way that they import nicely into MapIt.
This import script solves that problem, importing the CCG boundaries cleanly.
This may be useful to pull into master for users self-hosting, or could be useful for mapit uk if you decide to publish the CCG boundaries (as raised in issue #74).

[dracos]

I realise this copies the previous PR you mention, but is there a reason this command isn't a subclass of the mapit_import Command? I can't obviously see a reason why it has to use call_command and duplicate a lot of options/set up code, but I may well have missed something.

[chris48s]

Commits have been tidied as requested. I'll have a go at refactoring this based on your suggestions and get back to you with an updated pull request.

[chris48s]

I've refactored this to extend mapit_import, as requested. I've constructed an appropriate option_list by slicing mapit_import's option_list tuple. This solution is more succinct then redefining it but the downside to this is that adding or removing elements from the start or in the middle of mapit_import's option_list tuple would require updating the line:

    option_list = mapit_import.Command.option_list[:7] + \
                  mapit_import.Command.option_list[8:11] + \
                  mapit_import.Command.option_list[15:20]

accordingly.
Just something to be aware of there.

[dracos]

Thanks, that's a bit less code :) A suggestion for your downside - see how what I've done in 3175d64 uses create_parser to set defaults instead, doing it that way (or other similar things, perhaps remove_option) might save you having to do a slice, and be more robust.

[chris48s]

No problem - updated as requested.

[torotil]

I think this is outdated as the current CCG boundary files can be imported with the generic import command.

[chris48s]

Agreed 👍 Closing this and tidying up some other forgotten PRs that went nowhere