Fix links, lists formatings, typos, adding images and add detach interface.

...te/openstack/docs/additional-information/orchestration.md

.../openstack/docs/additional-information/security-groups.md

...ack/docs/getting-started/creating-first-infrastructure.md

...mpute/openstack/docs/how-to-guides/accessing-instances.md

topics/compute/openstack/docs/how-to-guides/create-router.md

...ompute/openstack/docs/how-to-guides/managing-interface.md

...compute/openstack/docs/how-to-guides/obtaining-api-key.md

...pute/openstack/docs/images/instance/institution_login.png

...mpute/openstack/docs/images/networks/detach_interface.png

...stack/docs/technical-reference/brno-g1-site/get-access.md

...stack/docs/technical-reference/brno-g1-site/networking.md

...stack/docs/technical-reference/brno-g2-site/get-access.md

...ute/openstack/docs/technical-reference/cloud-resources.md

...ck/docs/technical-reference/ostrava-g2-site/get-access.md