NGF: Add Deploy data plane doc

[bjee19]

Proposed changes

Add "Deploy Data plane document" to guide users on how to create and modify the NGINX Data Plane.

Problem: Users want a guide on how to create and modify the NGINX Data Plane.

Solution: Added the guide.

Testing: Tested with make watch

Closes nginx/nginx-gateway-fabric#3237

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• I have ensured my PR is targeting the main branch and pulling from my branch from my own fork
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• I have ensured that documentation content adheres to the style guide
• If the change involves potentially sensitive changes¹, I have assessed the possible impact
• If applicable, I have added tests that prove my fix is effective or that my feature works
• I have ensured that existing tests pass after adding my changes
• If applicable, I have updated README.md and CHANGELOG.md

Footnotes

1. Potentially sensitive changes include anything involving code, personally identify information (PII), live URLs or significant amounts of new or revised documentation. Please refer to our style guide for guidance about placeholder content. ↩

[ADubhlaoich]

Generally LGTM, but I have a lot of edit suggestions.

Shell examples are inconsistent: the start of the document delineates the shell command and the output into different code blocks, while later the command and output are put into the same blocks.

In the former case, a reader can easily copy the command - in the latter case, they cannot, and if they go to manually copy the command, they'll be forced to also strip away the shell prompts and other decorations.

I favour the former for general UX, but you can also just block the shell block and the text output together: no need to add text like "You should see these conditions".

[sjberman]

LGTM, pending the update to the label issue if we can fix that.

[mjang]

FYI, comment only: we have a definition for Data plane in our N1C glossary: https://docs.nginx.com/nginx-one/glossary/

[salonichf5]

small formatting edits and questions but lgtm