Build modified streamline images

The official image from streamline does not currently work for the arm64
platform. As a temporary measure, the source code and docker build scripts
have been lifted from the official images and are used to build locally.

Some additional modifications are made to reduce overall image size, these
are documented in docker/README.md

docker/streamline-src/vendor/laravel/serializable-closure/src/SerializableClosure.php

@@ -0,0 +1,139 @@
+<?php
+
+namespace Laravel\SerializableClosure;
+
+use Closure;
+use Laravel\SerializableClosure\Exceptions\InvalidSignatureException;
+use Laravel\SerializableClosure\Exceptions\PhpVersionNotSupportedException;
+use Laravel\SerializableClosure\Serializers\Signed;
+use Laravel\SerializableClosure\Signers\Hmac;
+
+class SerializableClosure
+{
+    /**
+     * The closure's serializable.
+     *
+     * @var \Laravel\SerializableClosure\Contracts\Serializable
+     */
+    protected $serializable;
+
+    /**
+     * Creates a new serializable closure instance.
+     *
+     * @param  \Closure  $closure
+     * @return void
+     */
+    public function __construct(Closure $closure)
+    {
+        if (\PHP_VERSION_ID < 70400) {
+            throw new PhpVersionNotSupportedException();
+        }
+
+        $this->serializable = Serializers\Signed::$signer
+            ? new Serializers\Signed($closure)
+            : new Serializers\Native($closure);
+    }
+
+    /**
+     * Resolve the closure with the given arguments.
+     *
+     * @return mixed
+     */
+    public function __invoke()
+    {
+        if (\PHP_VERSION_ID < 70400) {
+            throw new PhpVersionNotSupportedException();
+        }
+
+        return call_user_func_array($this->serializable, func_get_args());
+    }
+
+    /**
+     * Gets the closure.
+     *
+     * @return \Closure
+     */
+    public function getClosure()
+    {
+        if (\PHP_VERSION_ID < 70400) {
+            throw new PhpVersionNotSupportedException();
+        }
+
+        return $this->serializable->getClosure();
+    }
+
+    /**
+     * Create a new unsigned serializable closure instance.
+     *
+     * @param  Closure  $closure
+     * @return \Laravel\SerializableClosure\UnsignedSerializableClosure
+     */
+    public static function unsigned(Closure $closure)
+    {
+        return new UnsignedSerializableClosure($closure);
+    }
+
+    /**
+     * Sets the serializable closure secret key.
+     *
+     * @param  string|null  $secret
+     * @return void
+     */
+    public static function setSecretKey($secret)
+    {
+        Serializers\Signed::$signer = $secret
+            ? new Hmac($secret)
+            : null;
+    }
+
+    /**
+     * Sets the serializable closure secret key.
+     *
+     * @param  \Closure|null  $transformer
+     * @return void
+     */
+    public static function transformUseVariablesUsing($transformer)
+    {
+        Serializers\Native::$transformUseVariables = $transformer;
+    }
+
+    /**
+     * Sets the serializable closure secret key.
+     *
+     * @param  \Closure|null  $resolver
+     * @return void
+     */
+    public static function resolveUseVariablesUsing($resolver)
+    {
+        Serializers\Native::$resolveUseVariables = $resolver;
+    }
+
+    /**
+     * Get the serializable representation of the closure.
+     *
+     * @return array
+     */
+    public function __serialize()
+    {
+        return [
+            'serializable' => $this->serializable,
+        ];
+    }
+
+    /**
+     * Restore the closure after serialization.
+     *
+     * @param  array  $data
+     * @return void
+     *
+     * @throws \Laravel\SerializableClosure\Exceptions\InvalidSignatureException
+     */
+    public function __unserialize($data)
+    {
+        if (Signed::$signer && ! $data['serializable'] instanceof Signed) {
+            throw new InvalidSignatureException();
+        }
+
+        $this->serializable = $data['serializable'];
+    }
+}