Separated flow when installing different certificate types

This is part of the changes to improve the UX and language for installing certificates.
Previously when installing a certificate, the same dialog appeared for all certificates.
This CL introduces a separate flow for the different types:
 - CA certificate: confirm credential, select certificate, install
 - User certificate: select certificate, name dialog, install to keystore
 - WiFi certificate: select certificate, install to keystore

Bug: 139173976
Test: manual testing by installing different certificate types: CA, User and WiFi
      Including testing certificate which needs to be extracted
      go/enterprise-wifi-lab-access

Screenshot of the screen: https://hsv.googleplex.com/5666804900823040

Change-Id: I9b24c37b382eeecee6e5d0d74cbd4047c6d36182
7 files changed