feat: add grpc to glossary

[Sonichigo]

Describe your changes

This pull request adds a new conceptual documentation page for gRPC, covering its purpose, benefits, and use cases in modern distributed systems and microservices architectures.

• Added content/en/grpc.md to provide an overview of gRPC, including its architecture (HTTP/2, Protocol Buffers), the problems it solves in distributed systems, and its advantages for microservices, streaming, and interoperability.

Related issue number or link (ex: resolves #issue-number)

resolves #1038

Checklist before opening this PR (put x in the checkboxes)

• [x] This PR does not contain plagiarism
  • don’t copy other people’s work unless you are quoting and contributing it to them.
• [x] I have signed off on all commits
  • signing off (ex: git commit -s) is to affirm that commits comply DCO. If you are working locally, you could add an alias to your gitconfig by running git config --global alias.ci "commit -s".

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[Sonichigo]

@chalin I have resolved the comments!

@gnossen @ejona86 @thisisnotapril can I get feedback/suggestion on this PR?

[Sonichigo]

@iamNoah1 @nate-double-u can i get review?

[chalin]

@Sonichigo - can you address the comments?

[GoldenLion7]

@chalin may I give it a try?

[GoldenLion7]

Anyone or @chalin I want to help with documentation or if anything else open and u want me to work upon

[Sonichigo]

@chalin may I give it a try?

Hi @GoldenLion7 I'm still working on this one. You can pickup issues relevant from here - https://github.com/cncf/glossary/issues?q=is%3Aissue%20state%3Aopen%20no%3Aassignee

[GoldenLion7]

@Sonichigo no worries, go ahead. Take your time :)

[Sonichigo]

@nate-double-u can you check the following PR. I have updated it based on the guidelines and suggestion based on earlier reviewer's left has previously been included.