Added "update-url" command to find/replace url in the database

- Also aligned format of command descriptions.

Targeted most common columns.
Have not done revisions for the sake of keeping that
content true to how it was originally stored but could
cause unexpected behaviour.

For #1225

app/Console/Commands/UpdateUrl.php

@@ -0,0 +1,91 @@
+<?php
+
+namespace BookStack\Console\Commands;
+
+use Illuminate\Console\Command;
+use Illuminate\Database\Connection;
+
+class UpdateUrl extends Command
+{
+    /**
+     * The name and signature of the console command.
+     *
+     * @var string
+     */
+    protected $signature = 'bookstack:update-url
+                            {oldUrl : URL to replace}
+                            {newUrl : URL to use as the replacement}';
+
+    /**
+     * The console command description.
+     *
+     * @var string
+     */
+    protected $description = 'Find and replace the given URLs in your BookStack database';
+
+    protected $db;
+
+    /**
+     * Create a new command instance.
+     *
+     * @return void
+     */
+    public function __construct(Connection $db)
+    {
+        $this->db = $db;
+        parent::__construct();
+    }
+
+    /**
+     * Execute the console command.
+     *
+     * @return mixed
+     */
+    public function handle()
+    {
+        $oldUrl = str_replace("'", '', $this->argument('oldUrl'));
+        $newUrl = str_replace("'", '', $this->argument('newUrl'));
+
+        $urlPattern = '/https?:\/\/(.+)/';
+        if (!preg_match($urlPattern, $oldUrl) || !preg_match($urlPattern, $newUrl)) {
+            $this->error("The given urls are expected to be full urls starting with http:// or https://");
+            return 1;
+        }
+
+        if (!$this->checkUserOkayToProceed($oldUrl, $newUrl)) {
+            return 1;
+        }
+
+        $columnsToUpdateByTable = [
+            "attachments" => ["path"],
+            "pages" => ["html", "text", "markdown"],
+            "images" => ["url"],
+            "comments" => ["html", "text"],
+        ];
+
+        foreach ($columnsToUpdateByTable as $table => $columns) {
+            foreach ($columns as $column) {
+                $changeCount = $this->db->table($table)->update([
+                    $column => $this->db->raw("REPLACE({$column}, '{$oldUrl}', '{$newUrl}')")
+                ]);
+                $this->info("Updated {$changeCount} rows in {$table}->{$column}");
+            }
+        }
+
+        $this->info("URL update procedure complete.");
+        return 0;
+    }
+
+    /**
+     * Warn the user of the dangers of this operation.
+     * Returns a boolean indicating if they've accepted the warnings.
+     */
+    protected function checkUserOkayToProceed(string $oldUrl, string $newUrl): bool
+    {
+        $dangerWarning = "This will search for \"{$oldUrl}\" in your database and replace it with  \"{$newUrl}\".\n";
+        $dangerWarning .= "Are you sure you want to proceed?";
+        $backupConfirmation = "This operation could cause issues if used incorrectly. Have you made a backup of your existing database?";
+
+        return $this->confirm($dangerWarning) && $this->confirm($backupConfirmation);
+    }
+}