Add Bicep RPC client library documentation

[Gijsreyn]

Description

This pull request adds documentation around using the Azure.Bicep.RpcClient library.

Example Usage

N/A.

Checklist

• I have read and adhere to the contribution guide.

Microsoft Reviewers: Open in CodeFlow

[Gijsreyn]

@anthony-c-martin - I noticed that #18151 had the label Docs not needed, but I guess stubborn me thought it would be helpful to end-users to guide them through to get started with the new library added. Feel free to leave comments/feedback, accept it, or reject it.

[anthony-c-martin]

@anthony-c-martin - I noticed that #18151 had the label Docs not needed, but I guess stubborn me thought it would be helpful to end-users to guide them through to get started with the new library added. Feel free to leave comments/feedback, accept it, or reject it.

This is great! The label is just there to keep track of official docs requests (for docs.microsoft.com) with our documentation team. We're very happy to include developer-focused documentation in this repo.