Image stuff (#77)

Features
---------
Image to PDF supports multiple images, stretching and auto rotation
File inputs now only search for wanted file type
Settings now has a zip range so it can zip if you have more than x downloads (default 4)

extras
---------
DevTools support for easier development
Fix for temporary files for thread safety

src/main/resources/templates/ocr-pdf.html

@@ -16,7 +16,7 @@
                         <h2 th:text="#{ocr.header}"></h2>
 
 						 <form action="#" th:action="@{/ocr-pdf}" method="post" enctype="multipart/form-data" class="mb-3">
-				            <div th:replace="~{fragments/common :: fileSelector(name='fileInput', multiple=false)}"></div>
+				            <div th:replace="~{fragments/common :: fileSelector(name='fileInput', multiple=false, accept='application/pdf')}"></div>
 				            <div class="form-group">
 							    <label for="languages" class="form-label" th:text="#{ocr.selectText.1}"></label>
 							    <div id="languages">