.*: change llm-instance-gateway -> gateway-api-inference-extension

[MadhavJivrajani]

This PR renames the main module from inference.networking.x-k8s.io/llm-instance-gateway to inference.networking.x-k8s.io/gateway-api-inference-extension and also changes the name in module imports and some scripts.

Note: I've also changed the name in comments that include the old repo name. While this isn't strictly needed since GitHub has redirects in place, I'm not sure if those redirects will always remain.

Fixes #159

[MadhavJivrajani]

/assign @danehans

[MadhavJivrajani]

There's also https://github.com/kubernetes-sigs/gateway-api-inference-extension/blob/main/PROJECT

Considering this was generated at bootstrap time and edited once after the API was renamed, is it okay we edit this manually?

[ahg-g]

There's also https://github.com/kubernetes-sigs/gateway-api-inference-extension/blob/main/PROJECT

Considering this was generated at bootstrap time and edited once after the API was renamed, is it okay we edit this manually?

We can change it manually

[MadhavJivrajani]

Done @ahg-g, thanks!

[ahg-g]

/lgtm
/approve

Thanks!

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ahg-g, MadhavJivrajani

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [ahg-g]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment