docs: Steps for migrating to Envoy Gateway

[Manoramsharma]

What type of PR is this?
docs: Add a doc that can help users who want to migrate to Envoy Gateway

What this PR does / why we need it:
This PR highlights the ingress2gateway tool that can facilitate the migration to envoy gateway

Which issue(s) this PR fixes:

Fixes #3742

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 67.58%. Comparing base (eeb62c8) to head (de5550b).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3973      +/-   ##
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- Coverage   67.59%   67.58%   -0.01%     
==========================================
  Files         186      186              
  Lines       22757    22757              
==========================================
- Hits        15383    15381       -2     
- Misses       6268     6270       +2     
  Partials     1106     1106              

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[Manoramsharma]

@arkodg PTAL once !!!

[arkodg]

thanks !
this is a good start, we can further enhance this doc in the future

[Xunzhuo]

Should we mention that we need to configure the gatewayclass?

[Manoramsharma]

Should we mention that we need to configure the gatewayclass?

Yes , we can . Could you please mention in which step, I will add this.

[arkodg]

hey @Manoramsharma will the generated output be good enough or does the user need to also create a GatewayClass to link to the Envoy Gateway controller to ensure that the generated `HTTPRoutes`` get programmed in the data plane ?

[Manoramsharma]

hey @Manoramsharma will the generated output be good enough or does the user need to also create a GatewayClass to link to the Envoy Gateway controller to ensure that the generated `HTTPRoutes`` get programmed in the data plane ?

Hi @arkodg you are right, GatewayClass defines the controller responsible for managing Gateways and programming the data plane. Without this linkage, the Gateway controller won't know which resources it should handle, and the generated HTTPRoutes won't be programmed correctly.

Let me just update the PR mentioning the steps to configure the Gateway class.