feat: use webui API in NMS

[patriciareinoso]

Description

This PR removes the internal NMS backend and have the client interface query the webui API directly.

Breaking change. It uses new Rock version 1.0.0

• Remove all the files under pages/, which correspond to the internal NMS backend.
• Create call*Api.tsx files, which contain the calls to the webui API (subscribers, networks slices and device groups).
• Update URL to fetch the gnb and the upf list, which is now served by the webui.
• Update URL to fetch the swagger UI, which is now served by the webui.
• Change next.config.js : it contains the configuration to export the NMS into static files when building. Parameters that are no longer necessary were removed.
• Redirection from / to /network-configuration is placed on app/page.tsx
• Remove files not used: DeleteSubscriberButton.tsx, checkNetworkSliceExists.tsx
• Rename to Aether SD-Core
• Disable API link while waiting for feat: Add swagger UI omec-project/webconsole#193

This PR depends on the following PRs:

• feat: Add static file serving support in webconsole omec-project/webconsole#191
• feat: config gNBs and UPFs omec-project/webconsole#194

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code.
• I have made corresponding changes to the documentation.
• I have added tests that validate the behaviour of the software.
• I validated that new and existing unit tests pass locally with my changes.
• Any dependent changes have been merged and published in downstream modules.

[gatici]

Looks good. Minor things are commented for improvement.