Add SGI and TGA preview support

Signed-off-by: John Molakvoæ (skjnldsv) <skjnldsv@protonmail.com>

lib/private/Preview/SGI.php

+<?php
+/**
+ * @copyright 2021 John Molakvoæ <skjnldsv@protonmail.com>
+ *
+ * @author John Molakvoæ <skjnldsv@protonmail.com>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+namespace OC\Preview;
+
+//.sgi
+class SGI extends Bitmap {
+	/**
+	 * {@inheritDoc}
+	 */
+	public function getMimeType(): string {
+		return '/image\/sgi/';
+	}
+}

lib/private/Preview/TGA.php

+<?php
+/**
+ * @copyright 2021 John Molakvoæ <skjnldsv@protonmail.com>
+ *
+ * @author John Molakvoæ <skjnldsv@protonmail.com>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+namespace OC\Preview;
+
+//.tga
+class TGA extends Bitmap {
+	/**
+	 * {@inheritDoc}
+	 */
+	public function getMimeType(): string {
+		return '/image\/t(ar)?ga/';
+	}
+}

lib/private/PreviewManager.php

  *
  * @author Christoph Wurst <christoph@winzerhof-wurst.at>
  * @author Joas Schilling <coding@schilljs.com>
- * @author John Molakvoæ (skjnldsv) <skjnldsv@protonmail.com>
+ * @author John Molakvoæ <skjnldsv@protonmail.com>
  * @author Julius Härtl <jus@bitgrid.net>
  * @author Morris Jobke <hey@morrisjobke.de>
  * @author Olivier Paroz <github@oparoz.com>
 				'EPS' => ['mimetype' => '/application\/postscript/', 'class' => Preview\Postscript::class],
 				'TTF' => ['mimetype' => '/application\/(?:font-sfnt|x-font$)/', 'class' => Preview\Font::class],
 				'HEIC' => ['mimetype' => '/image\/hei(f|c)/', 'class' => Preview\HEIC::class],
+				'TGA' => ['mimetype' => '/image\/t(ar)?ga/', 'class' => Preview\TGA::class],
+				'SGI' => ['mimetype' => '/image\/sgi/', 'class' => Preview\SGI::class],
 			];
 
 			foreach ($imagickProviders as $queryFormat => $provider) {

resources/config/mimetypealiases.dist.json

 	"application/internet-shortcut": "link",
 	"application/km": "mindmap",
 	"application/x-freemind": "mindmap",
-	"application/vnd.xmind.workbook": "mindmap"
+	"application/vnd.xmind.workbook": "mindmap",
+	"image/targa": "image/tga",
+	"image/targa": "image/tga"
 }
 

resources/config/mimetypemapping.dist.json

 	"rw2": ["image/x-dcraw"],
 	"schema": ["text/plain"],
 	"sgf": ["application/sgf"],
+	"sgi": ["image/sgi"],
 	"sh-lib": ["text/x-shellscript"],
 	"sh": ["text/x-shellscript"],
 	"srf": ["image/x-dcraw"],
 	"tbz2": ["application/x-bzip2"],
 	"tcx": ["application/vnd.garmin.tcx+xml"],
 	"tex": ["application/x-tex"],
+	"tga": ["image/tga"],
 	"tgz": ["application/x-compressed"],
 	"tiff": ["image/tiff"],
 	"tif": ["image/tiff"],