[FEATURE] Introduce Site Sets

As a site set can only be used in TYPO3 v13
we can use the new constant syntax
{$plugin.tx_ttaddress.view.templateRootPath ?? $tt_address.templateRootPath} here.
The TypoScript will not be included by v12 installations.

resolves FriendsOfTYPO3#570

Configuration/Sets/Address/config.yaml

@@ -0,0 +1,2 @@
+name: friendsoftypo3/tt-address
+label: Addresses (Extbase/Fluid)

Configuration/Sets/Address/settings.definitions.yaml

@@ -0,0 +1,16 @@
+settings:
+  tt_address.templateRootPath:
+    label: 'Path to template root (FE)'
+    description: ''
+    type: string
+    default: 'EXT:tt_address/Resources/Private/Templates/'
+  tt_address.partialRootPath:
+    label: 'Path to template partials (FE)'
+    description: ''
+    type: string
+    default: 'EXT:tt_address/Resources/Private/Partials/'
+  tt_address.layoutRootPath:
+    label: 'Path to template layouts (FE)'
+    description: ''
+    type: string
+    default: 'EXT:tt_address/Resources/Private/Layouts/'

Configuration/Sets/Address/setup.typoscript

@@ -0,0 +1,14 @@
+@import 'EXT:tt_addressConfiguration/TypoScript/setup.typoscript'
+plugin.tx_ttaddress {
+    view {
+        templateRootPaths {
+            1 = {$plugin.tx_ttaddress.view.templateRootPath ?? $tt_address.templateRootPath}
+        }
+        partialRootPaths {
+            1 = {$plugin.tx_ttaddress.view.partialRootPath ?? $tt_address.partialRootPath}
+        }
+        layoutRootPaths {
+            1 = {$plugin.tx_ttaddress.view.layoutRootPath ?? $tt_address.layoutRootPath}
+        }
+    }
+}