Remove custom Twig extensions

Go back to calculating the talk count inline and using a macro to get
the number of years experience.

composer.json

@@ -8,18 +8,5 @@
         "allow-plugins": {
             "sculpin/sculpin-theme-composer-plugin": true
        }
-    },
-    "autoload": {
-        "psr-4": {
-            "App\\": "src/"
-        }
-   },
-    "autoload-dev": {
-        "psr-4": {
-            "Tests\\": "tests/"
-        }
-   },
-    "require-dev": {
-        "phpunit/phpunit": "^11.1"
     }
 }