feat: reverse shares (#86)

* add first concept

* add reverse share funcionality to frontend

* allow creator to limit share expiration

* moved reverse share in seperate module

* add table to manage reverse shares

* delete complete share if reverse share was deleted

* optimize function names

* add db migration

* enable reverse share email notifications

* fix config variable descriptions

* fix migration for new installations

frontend/src/components/upload/FileList.tsx

@@ -2,7 +2,7 @@ import { ActionIcon, Table } from "@mantine/core";
 import { Dispatch, SetStateAction } from "react";
 import { TbTrash } from "react-icons/tb";
 import { FileUpload } from "../../types/File.type";
-import { byteStringToHumanSizeString } from "../../utils/math/byteStringToHumanSizeString.util";
+import { byteToHumanSizeString } from "../../utils/fileSize.util";
 import UploadProgressIndicator from "./UploadProgressIndicator";
 
 const FileList = ({
@@ -19,7 +19,7 @@ const FileList = ({
   const rows = files.map((file, i) => (
     <tr key={i}>
       <td>{file.name}</td>
-      <td>{byteStringToHumanSizeString(file.size.toString())}</td>
+      <td>{byteToHumanSizeString(file.size)}</td>
       <td>
         {file.uploadingProgress == 0 ? (
           <ActionIcon