master: allow to choose database type

manifests/roles/master.pp

-class icinga2_testing::roles::master
-{
+class icinga2_testing::roles::master(
+  $database = 'mysql',
+) {
+  validate_re($database, '^(mysql|pgsql)$', "Unsupported database type: ${database}")
+
   include ::icinga2_testing::roles::base
 
   contain ::icinga2_testing::profiles::repository
 
-  contain ::icinga2_testing::profiles::mysql
-  Class['icinga2_testing::profiles::mysql'] -> Class['icinga2_testing::helpers::icinga2::ido_mysql']
+  contain "::icinga2_testing::profiles::${database}"
+  Class["::icinga2_testing::profiles::${database}"] -> Class["::icinga2_testing::helpers::icinga2::ido_${database}"]
 
   contain ::icinga2_testing::profiles::icinga2
-  contain ::icinga2_testing::helpers::icinga2::ido_mysql
+  contain "::icinga2_testing::helpers::icinga2::ido_${database}"
 
   contain ::icinga2_testing::profiles::icingaweb2