update links overall

content/en/docs/about/_index.md

content/en/docs/about/contributors-funders.md

content/en/docs/manual/best-practices.md

content/en/docs/manual/connecting/index.md

content/en/docs/manual/job-submission/kerberos.md

content/en/docs/manual/job-submission/priorities.md

content/en/docs/manual/job-submission/slurm-basics.md

content/en/docs/manual/software/installing-software.md

content/en/docs/system/compute-nodes.md

content/en/docs/system/storage.md

content/en/docs/system/tud-clusters.md

content/en/quickstart/_index.md