Create an offline snapshot for air-gapped installation docs

## Why?
We have a group of customers that need to view all air-gapped installation docs in a single location. Since these customers don't have access to public internet, we should provide them with an offline snapshot of these air-gapped install docs.

## Existing air-gapped installation docs and current owners
- Logstash (David K and Karen): [https://www.elastic.co/guide/en/logstash/8.5/plugins-filters-geoip.html#plugins-filters-geoip-manage_update](https://www.elastic.co/guide/en/logstash/8.5/plugins-filters-geoip.html#plugins-filters-geoip-manage_update)
- Logstash *maybe* (David K and Karen): [https://www.elastic.co/guide/en/logstash/current/offline-plugins.html](https://www.elastic.co/guide/en/logstash/current/offline-plugins.html)
- Fleet and Elastic Agent Guide (Karen): [https://www.elastic.co/guide/en/fleet/current/air-gapped.html](https://www.elastic.co/guide/en/fleet/current/air-gapped.html)
- Fleet and Elastic Agent (Karen): [https://www.elastic.co/guide/en/fleet/7.17/fleet-overview.html#package-registry-intro](https://www.elastic.co/guide/en/fleet/7.17/fleet-overview.html#package-registry-intro)
- Elastic Cloud on Kubernetes (Arianna): [https://www.elastic.co/guide/en/cloud-on-k8s/master/k8s-air-gapped.html](https://www.elastic.co/guide/en/cloud-on-k8s/master/k8s-air-gapped.html)
- ECE (Arianna): [https://www.elastic.co/guide/en/cloud-enterprise/3.5/ece-install-offline.html](https://www.elastic.co/guide/en/cloud-enterprise/3.5/ece-install-offline.html)

## Supporting docs
- [https://discuss.elastic.co/t/upgrading-elastic-agent-via-fleet-in-an-air-gapped-environment-failing/297413](https://discuss.elastic.co/t/upgrading-elastic-agent-via-fleet-in-an-air-gapped-environment-failing/297413)
- [https://github.com/wise2c-devops/install-elastic-cloud-on-k8s](https://github.com/wise2c-devops/install-elastic-cloud-on-k8s)
- [https://github.com/elastic/kibana/issues/74614](https://github.com/elastic/kibana/issues/74614)

## Discussion points
- External dependencies
- Offline doc ownership
- Breaking changes ownership
- Potential home: [Elastic Installation and Upgrade Guide](https://www.elastic.co/guide/en/elastic-stack/current/index.html)

Rà soát các trang cài đặt air-gapped của Logstash, Fleet và Elastic Agent, ECK và ECE được liệt kê, cùng với các liên kết hỗ trợ. Bắt đầu bằng cách lập bản đồ các dependency bên ngoài, quyền sở hữu và trách nhiệm đối với breaking changes, sau đó đánh giá vị trí được đề xuất cho Elastic Installation and Upgrade Guide. Được xem là hoàn tất khi khách hàng có thể truy cập toàn bộ tài liệu cài đặt air-gapped liên quan trong một snapshot offline duy nhất.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.