Improve Sandbox Setup instructions

- make clearer which ini file should be updated with the users credentials
- improve hierarchy and naming of headings
- insert table of contents
- replace some inline code with code blocks to make commands more visible

Issue-ID: CIMAN-430

Signed-off-by: Fiete Ostkamp <Fiete.Ostkamp@telekom.de>
Change-Id: Ic423be1cec19ab68e05c8c30681fb1d19f482679
1 file changed