Remove credential management app Settings

* Update string and icon
* Flip icon if languate is RTL e.g. Arabic
* Add dialog when 'Remove app' is selected
* Add Material Next theme to dialog
* Update string terminology when removing a
  CA or user certificate to from 'remove'
  to 'uninstall'
* Final UI tweaks to RequestManageCredentials screen

Screenshots
* Light mode: https://screenshot.googleplex.com/66QKFLhtn6ZueZQ
* Dark mode: https://screenshot.googleplex.com/9kkTaaDV6CiHudF
* RTL: https://screenshot.googleplex.com/AkwSibXakARYM8H
* Request light mode: https://screenshot.googleplex.com/6n6raBQ8drXRHcU
* Request dark mode: https://screenshot.googleplex.com/3bmWNoTwE6JBqAX

Bug: 189416800
Test: atest CredentialManagementAppButtonsControllerTest
      manual testing with TestDPC
Change-Id: I5450d33603418930e92b03c4447aaa1095afe9a3

src/com/android/settings/security/RequestManageCredentials.java

@@ -288,7 +288,7 @@ public class RequestManageCredentials extends Activity {
                     // On down scroll, hide text in floating action button by setting
                     // extended to false.
                     if (dy > 0 && mExtendedFab.getVisibility() == View.VISIBLE) {
-                        mExtendedFab.setExtended(false);
+                        mExtendedFab.shrink();
                     }
                     if (isRecyclerScrollable()) {
                         mExtendedFab.show();