BP Blocks: one panel for all block settings

[imath]

We've been talking about it yesterday during our dev-chat: @greenshady wrote a ​great post on WPTavern to share about the BP Blocks feature. In this post he also shared a very interesting feedback:

The only trivial gripe I have with the new blocks is how the block settings are handled. Each setting is placed within its own tabbed section. It does not make sense to open or close four tabs to get to a single setting for each.

And I totally agree. We don't need a panel for each setting. Once we'll have more settings for a feature, we'll be able to add Panels.

[imath]

Here are screenshots of how it would look for:

The Member block

The Group block

[espellcaste]

Not sure if we have the time but it'd be great if we had that in. Patch looks good.

[imath]

I'll include it into beta2 ;)

[imath]

In 12618:

BP Blocks: gather all settings into a unique panel

Props greenshady

Fixes #8271