add documentation for g2 brno site

topics/compute/openstack/docs/additional-information/faq.md

...compute/openstack/docs/additional-information/register.md

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

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

...ute/openstack/docs/how-to-guides/managing-floating-ips.md

topics/compute/openstack/docs/index.md

...te/openstack/docs/technical-reference/brno-g1-site/faq.md

...penstack/docs/technical-reference/brno-g1-site/flavors.md

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

...tack/docs/technical-reference/brno-g1-site/get-support.md

...ck/docs/technical-reference/brno-g1-site/gpu-computing.md

.../openstack/docs/technical-reference/brno-g1-site/index.md

...ocs/technical-reference/brno-g1-site/instance-shelving.md

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

.../technical-reference/brno-g1-site/openstack-components.md

...ack/docs/technical-reference/brno-g1-site/quota-limits.md

...te/openstack/docs/technical-reference/brno-g2-site/faq.md

...penstack/docs/technical-reference/brno-g2-site/flavors.md

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

...tack/docs/technical-reference/brno-g2-site/get-support.md