Better screen transitions (#4285)

I mostly took Android 13 transitions and removed the sliding for the
"deeper"/background one because "extend" animations are not available
until Android 13.

Here are the original ones:
https://cs.android.com/android/platform/superproject/+/android-13.0.0_r8:frameworks/base/core/res/res/anim/;bpv=1

Initially I've made separate versions fro Android 13+ that are close to
the original but I think it's not worth it to keep both.



https://github.com/tuskyapp/Tusky/assets/3099142/616fc40c-f944-45b4-bf6f-167f62d30493

app/src/main/java/com/keylesspalace/tusky/fragment/SFragment.kt

@@ -84,7 +84,7 @@ abstract class SFragment : Fragment(), Injectable {
 
     override fun startActivity(intent: Intent) {
         super.startActivity(intent)
-        requireActivity().overridePendingTransition(R.anim.slide_from_right, R.anim.slide_to_left)
+        requireActivity().overridePendingTransition(R.anim.activity_open_enter, R.anim.activity_open_exit)
     }
 
     override fun onAttach(context: Context) {