kuksa-val: Add root CA certificate to agl-driver nssdb

kuksa-val: Add root CA certificate to agl-driver nssdb

This change is needed by chromium to fix the ERR_CERT_AUTHORITY_INVALID
issued when trying to connect to kuksa.val server using a secure
connection.

chromium is shipped with a read-only database containing trusted
CA certs and also uses a local nss database (stored on the user home
directory) that can be managed by the nss command line tools.

This change adds the kuksa root CA to agl-driver's nssdb
that can be loaded by chromium and used to perform validation.

v2 (jsmoeller): Use separate package for pki db in agl-driver home.

Bug-AGL: SPEC-4599
Signed-off-by: Roger Zanoni <rzanoni@igalia.com>
Signed-off-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>
Change-Id: I074d48fedfadaddd9a894b478839e16fa4757b5e