I would like to customize the listing of the chapters given in the table of contents in a `scrbook` document. Given the following example:

```
\documentclass{scrbook}
\begin{document}
\tableofcontents
\chapter{Alpha}
\chapter{Beta}
\chapter{Gamma}
\end{document}

```

My TOC currently looks like this:

![TOC](https://i.stack.imgur.com/4GVUY.png)

How can I customize the text printed in the TOC in the following two regards:

* add a prefix/suffix to the number, e.g. write "Chapter 1" instead of "1"
* increase letter spacing of the chapter title using `microtype`'s `textls`