Remove custom Twig extensions

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

src/Experience/ExperienceTwigExtension.php

@@ -1,29 +0,0 @@
-<?php
-
-namespace App\Experience;
-
-use Sculpin\Contrib\ProxySourceCollection\ProxySourceItem;
-use Twig\Extension\AbstractExtension;
-use Twig\TwigFunction;
-
-class ExperienceTwigExtension extends AbstractExtension
-{
-    private static $startYear = 2007;
-
-    public function getFunctions(): array
-    {
-        return [
-            new TwigFunction('get_years_of_experience', [$this, 'getYearsOfExperience']),
-        ];
-    }
-
-    public function getName(): string
-    {
-        return 'experience';
-    }
-
-    public function getYearsOfExperience(): int
-    {
-        return (new \DateTimeImmutable())->format('Y') - self::$startYear;
-    }
-}

src/Presentations/PresentationTwigExtension.php

@@ -1,38 +0,0 @@
-<?php
-
-namespace App\Presentations;
-
-use Sculpin\Contrib\ProxySourceCollection\ProxySourceItem;
-use Twig\Extension\AbstractExtension;
-use Twig\TwigFunction;
-
-class PresentationTwigExtension extends AbstractExtension
-{
-    public function getFunctions(): array
-    {
-        return [
-            new TwigFunction('get_presentation_count', [$this, 'getPresentationCount']),
-        ];
-    }
-
-    public function getName(): string
-    {
-        return 'presentations';
-    }
-
-    public function getPresentationCount(array $presentations): int
-    {
-        $today = (new \DateTime('today'))->getTimestamp();
-
-        return collect($presentations)
-            ->flatMap(fn (ProxySourceItem $presentation) => $presentation->data()->get('events'))
-            ->filter(
-                function (array $event) use ($today): bool {
-                    assert(array_key_exists(array: $event, key: 'date'));
-
-                    return $event['date'] < $today;
-                }
-            )
-            ->count();
-    }
-}