Move plugins to manifest, pin Docker version, add Makefile

- Add plugins.txt listing all plugins for reproducible installs
- Add Makefile with setup/start/stop/install-plugins targets
- Remove user/plugins/ from git tracking
- Pin Docker image to 1.7.49.5-ls244

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

plugins/admin/vendor/laminas/laminas-xml/composer.json

@@ -1,55 +0,0 @@
-{
-    "name": "laminas/laminas-xml",
-    "description": "Utility library for XML usage, best practices, and security in PHP",
-    "license": "BSD-3-Clause",
-    "keywords": [
-        "laminas",
-        "xml",
-        "security"
-    ],
-    "homepage": "https://laminas.dev",
-    "support": {
-        "issues": "https://github.com/laminas/laminas-xml/issues",
-        "source": "https://github.com/laminas/laminas-xml",
-        "rss": "https://github.com/laminas/laminas-xml/releases.atom",
-        "chat": "https://laminas.dev/chat",
-        "forum": "https://discourse.laminas.dev"
-    },
-    "config": {
-        "sort-packages": true
-    },
-    "require": {
-        "php": "^7.3 || ~8.0.0 || ~8.1.0",
-        "ext-dom": "*",
-        "ext-simplexml": "*"
-    },
-    "require-dev": {
-        "laminas/laminas-coding-standard": "~1.0.0",
-        "squizlabs/php_codesniffer": "3.6.1 as 2.9999999.9999999",
-        "phpunit/phpunit": "^9.5.8",
-        "ext-iconv": "*"
-    },
-    "autoload": {
-        "psr-4": {
-            "Laminas\\Xml\\": "src/"
-        }
-    },
-    "autoload-dev": {
-        "psr-4": {
-            "LaminasTest\\Xml\\": "test/"
-        }
-    },
-    "scripts": {
-        "check": [
-            "@cs-check",
-            "@test"
-        ],
-        "cs-check": "phpcs",
-        "cs-fix": "phpcbf",
-        "test": "phpunit --colors=always",
-        "test-coverage": "phpunit --colors=always --coverage-clover clover.xml"
-    },
-    "conflict": {
-        "zendframework/zendxml": "*"
-    }
-}