Bug 926334 - [Gaia] To support WPA-EAP options(PEAP, TLS, TTLS) and manage certificate in WLAN setting. 

A copy pull request from https://github.com/mozilla-b2g/gaia/pull/13989

According to user story of Bug 926341, we have to support WPA-EAP settings option(PEAP, TLS, TTLS) in this bug.

* Add new three pages `wifi-manageCertificate`, `wifi-selectCertificateFile`, and `wifi-enterCertificateNickname`.
* Maintain imported server certificate list.(`gCertificateList`)
* Maintain browsing files from SDCard to import certificate file.(`gSelectCertificateFiles`)
* Given phase 2 authentication, server certificate option for setting WPA-EAP method = PEAP/TLS/TTLS
* Add error dialog for error case.(import/delete certificate file failed)
* Support auto-detection API.
  - If platform certificate manager API is not ready yet, we will hide all of the relative feature and layout.
  - So, the landing process won't be blocking by platform side.