Use simplified ssh commands

A default configuration for ssh is given on https://doc.zih.tu-dresden.de/access/ssh_login/ which simplifies ssh <zih-login>@tauruslogin.hrsk.tu-dresden.de to ssh taurus. However, only few pages use it. Thus, replace where possible and add a link to ssh_login.md like on https://doc.zih.tu-dresden.de/data_transfer/export_nodes/. This might also help Windows users, as access via PuTTY is also on the page ssh_login.md. These pages use ssh commands:

• doc.zih.tu-dresden.de/docs/access/graphical_applications_with_webvnc.md
• doc.zih.tu-dresden.de/docs/contrib/content_rules.md
• doc.zih.tu-dresden.de/docs/software/hyperparameter_optimization.md
• doc.zih.tu-dresden.de/docs/software/tensorboard.md
• doc.zih.tu-dresden.de/docs/software/vampir.md
• doc.zih.tu-dresden.de/docs/software/visualization.md

These pages use scp commands:

• doc.zih.tu-dresden.de/docs/software/mathematics.md