Improve documentation for MutliDeviceFactories

[jonnew]

• Add features to class description in bullet list format.
• Fixes ConfigureHeadstage64 constructor XML remarks should be moved to class description #273

[cjsha]

In each of the hubs, in the top-level remarks, you added these nice bulleted list of devices and their corresponding features. It might help to refer to your bulleted list as a list of devices in the device group because the summary for MultiDeviceFamily's Process method (which is going to be the next thing in the page after I change the template according to previous conversations), it says "Configure all devices in the device group". This implicitly defines what a device group is.

[cjsha]

I like what you're calling the headstages, they're following a format: Headstage-Abc (i.e. Headstage-NeuropixelsV2e). I think there's practicality in this uniformity. Though I'm not sure we need hyphens when it comes to human-readable content that goes in docs and store. And I think Headstage-NeuropixelsV2e-Beta should be Headstage-NeuropixelsV2eBeta instead

[cjsha]

This PR is approved but please go through and consider all the comments - I'm not sure it requires another review cycle after you address them (though you can re-request me if you want)