Document C# and JavaScript Static Client Proxies

[hikalkan]

Once #9905 merged and related issues are completed, we need to document it.
In addition to the documentation, we can also mention (as a short note) this feature in tutorials as an alternative way to consume HTTP APIs.

• Under the API -> Static C# API Clients just under the dynamic one.
• Under the UI -> MVC menu item, create "Static JavaScript API Client Proxies" just under the Dynamic one.

We can take the blog post "Static (Generated) Client Proxies for C# and JavaScript" section as a reference: https://blog.abp.io/abp/ABP-IO-Platform-5.0-RC-1-Has-Been-Released