Add RxPreferenceFragmentCompat component

[pawegio]

PreferenceFragmentCompat returns to grace with new android support library, since it's necessary if we want to use PreferenceDataStore below API level 26.

[dlew]

On the one hand: yes, this makes a lot of sense.

On the other hand, I don't want to add another transitive dependency for people who don't need it.

Thoughts?

[vanniktech]

The extra dependency is really unfortunate.

[pawegio]

Ok, I agree with both of you. What do you think about extracting it to another module, e.g. rxlifecycle-components-preference? I believe that it is reasonable since preference-v7 package comes with multiple fragments targeting different use cases such as:

• PreferenceFragmentCompat (already added in this PR)
• EditTextPreferenceDialogFragmentCompat
• PreferenceDialogFragmentCompat
• ListPreferenceDialogFragmentCompat

Since I am currently experimenting with preference data stores I can handle it.

[dlew]

Yeah. I think if we want to add this, it should be in its own dependency. It's more of a pain to setup initially but it saves a lot of headache for consumers.

It's how we should've done the original split between OS and support components, too. We could still go back and do it that way, in fact...

[pawegio]

Now it is extracted to its own dependency.

[dlew]

This is great, thanks!

[dlew]

I've pushed out v2.2.0 which includes this new artifact.