Add support for setting UserDir in Virtual Hosts

We can only set this setting at the VirtualHost level by relying on the
`custom_fragment` parameter, which does not scale when we want to enable
UserDir for a single VHost because we have to manually disable it on all
other VHosts.

With this change, one can ensure UserDir is active only on specific
VHost with something like:

```
Apache::Vhost {
  userdir => 'disabled',
}

apache::vhost { 'example.com':
  # [...]
  userdir => 'enabled',
}
```

A specific `userdir` parameter avoid clashes that would prevent this
technique to be effective with `custom_fragment`.

Author: smortex

manifests/vhost.pp

@@ -1995,6 +1995,7 @@
   Boolean $auth_oidc                                                                = false,
   Optional[Apache::OIDCSettings] $oidc_settings                                     = undef,
   Optional[Variant[Boolean,String]] $mdomain                                        = undef,
+  Optional[Variant[String[1],Array[String[1]]]] $userdir                            = undef,
 ) {
   # The base class must be included first because it is used by parameter defaults
   if ! defined(Class['apache']) {
@@ -2854,6 +2855,18 @@
     include apache::mod::md
   }
 
+  # Template uses:
+  # - $userdir
+  if $userdir {
+    include apache::mod::userdir
+
+    concat::fragment { "${name}-userdir":
+      target  => "${priority_real}${filename}.conf",
+      order   => 300,
+      content => template('apache/vhost/_userdir.erb'),
+    }
+  }
+
   # Template uses:
   # - $passenger_enabled
   # - $passenger_start_timeout

spec/defines/vhost_spec.rb

@@ -496,6 +496,7 @@
                                                  'ClientSecret'              => 'aae053a9-4abf-4824-8956-e94b2af335c8',
                                                  'CryptoPassphrase'          => '4ad1bb46-9979-450e-ae58-c696967df3cd' },
               'mdomain'                     => 'example.com example.net auto',
+              'userdir'                     => 'disabled',
             }
           end
 
@@ -2472,6 +2473,20 @@
             )
           }
         end
+
+        context 'userdir' do
+          let :params do
+            default_params.merge(
+              'userdir' => [
+                'disabled',
+                'enabled bob',
+              ],
+            )
+
+            it { is_expected.to contain_concat__fragment('rspec.example.com-apache-userdir').with(content: %r{^\s+UserDir disabled$}) }
+            it { is_expected.to contain_concat__fragment('rspec.example.com-apache-userdir').with(content: %r{^\s+UUserDir enabled bob$}) }
+          end
+        end
       end
     end
   end

templates/vhost/_userdir.erb

@@ -0,0 +1,3 @@
+  <%- [@userdir].flatten.each do |userdir| -%>
+  UserDir <%= userdir %>
+  <%- end -%>