feat: support installation as submodule

Closes #74

.gitignore

@@ -1,8 +1,29 @@
 node_modules/
 .DS_Store
 .idea/
-vendor/
-composer.lock
 yarn.lock
-vendor
 kirby
+
+# files of Composer dependencies that are not needed for the plugin
+# See https://getkirby.com/docs/guide/plugins/plugin-setup-composer
+/vendor/**/.*
+/vendor/**/*.json
+/vendor/**/*.txt
+/vendor/**/*.md
+/vendor/**/*.yml
+/vendor/**/*.yaml
+/vendor/**/*.xml
+/vendor/**/*.dist
+/vendor/**/readme.php
+/vendor/**/LICENSE
+/vendor/**/COPYING
+/vendor/**/VERSION
+/vendor/**/Makefile
+/vendor/**/phpstan.neon
+/vendor/**/docs/*
+/vendor/**/example/*
+/vendor/**/examples/*
+/vendor/**/test/*
+/vendor/**/tests/*
+/vendor/**/php4/*
+/vendor/getkirby/composer-installer

composer.json

@@ -34,6 +34,7 @@
     "kirby-cms-path": false
   },
   "config": {
+    "optimize-autoloader": true,
     "allow-plugins": {
       "getkirby/composer-installer": true
     }