Graphing Configuration for 2.17

These changes adjust the graph configuration modal slightly to support the additions and changes to the graph configuration options that will be introduced in 2.17. There is also a migration here to support the change of `x-lable-count` and `y-label-count` to `x-labels` and `y-labels`. There should only be a handful of apps that need to be altered.

**DO NOT MERGE** until 2.17 is released.
Ah, good to know. The two questions you posed are sort of tricky to answer in this situation I think because there is both the old/new code in HQ, and the old/new mobile code (because this PR should coincide with the 2.17 release)

**Does the new structure work in the old code or not?**
- old HQ code: Yes, the `x-labels` will appear in the graph configuration interface if that property is set on the graph. But, the graph configuration property typeahead will still include `x-label-count`, which might confuse the user.
- old mobile code: No, graphs in new builds won’t have the new `x-labels` property respected by the mobile app. Therefore, they will lose the `x-label-count` configuration that they may have had previously.

**Does the old structure work in the new code or not?**
- new HQ code: Yes, the `x-label-count` property will appear in the graph configuration interface if that property is set on the graph.
- new mobile code: No, graphs in old and new builds won’t have the old `x-label-count` property respected by the mobile app.

So based on your guidelines, since the migration won’t happen “in between” the mobile deploy any ways, I think perhaps the best thing to do is to run a management command to migrate the configuration properties immediately after the deploy? I guess I’m not totally sure what the advantage of doing that is though, since it seems like it adds a step to the deploy that could be run automatically?