THREESCALE-4185: Support TLS protection for external DBs (#3846)

* Support SSL Mysql

It works OOB, only a few env vars required

* Support SSL Postgresql

It works OOB, only a few env vars required

* Add new var `DATABASE_SSL_MODE` for Postgres

* Add `ssl_mode` for MySQL

config/examples/database.yml

@@ -25,6 +25,10 @@ base: &default
   pool: <%= ENV.fetch('RAILS_MAX_THREADS', 5) %>
   variables:
     timezone: 'UTC'
+  sslmode: <%= ENV.fetch('DATABASE_SSL_MODE', ENV.fetch('DATABASE_SSL_CA', nil) ? 'verify-full' : 'disable') %>
+  sslrootcert: <%= ENV['DATABASE_SSL_CA'] %>
+  sslcert: <%= ENV['DATABASE_SSL_CERT'] %>
+  sslkey: <%= ENV['DATABASE_SSL_KEY'] %>
 
 development:
   <<: *default
@@ -43,6 +47,10 @@ base: &default
   encoding: utf8
   pool: <%= ENV.fetch('RAILS_MAX_THREADS', 5) %>
   collation: utf8_bin
+  ssl_mode: <%= ENV.fetch('DATABASE_SSL_MODE', ENV.fetch('DATABASE_SSL_CA', nil) ? 'verify_identity' : 'disabled') %>
+  sslca: <%= ENV['DATABASE_SSL_CA'] %>
+  sslcert: <%= ENV['DATABASE_SSL_CERT'] %>
+  sslkey: <%= ENV['DATABASE_SSL_KEY'] %>
 
 development:
   <<: *default