Provide an alternative way to group auto-configuration together in the report

[snicoll]

Now that we have a reactive flavour for our data stores, we can see things like ReactiveFooDataAutoConfiguration alongside FooDataConfiguration. The naming sounds about right but information about foo are now split in two distinct areas of the auto-configuration report as we order them alphabetically.

One idea would be to group them by package which works for some part but not for everything as Data auto-configuration typically is split in two (a package for the data store when Spring Data isn't available and the Spring Data specific bits are located in another package).

Maybe we need a better semantic to group auto-configurations together?