🚀 Feature: Migrate SDk to Support to Kotlin MultiPlatform (KMP)

### 🔖 Feature description

Migrate lib to KMP structure and replace following:

- GSON -> kotlinx.serialization
- okhttp -> ktor

to support multiple targets like, Android, JVM, IOS, maybe Native too(for MacOS, Windows, Linux).

Are you open to PRs for same ?

### 🎤 Pitch

why keep kotlin sdk only scoped to jvm, Kotlin Targets more platforms.

### 👀 Have you spent some time to check if this issue has been raised before?

- [X] I checked and didn't find similar issue

### 🏢 Have you read the Code of Conduct?

- [X] I have read the [Code of Conduct](https://github.com/appwrite/appwrite/blob/HEAD/CODE_OF_CONDUCT.md)

The issue names no files, tests, or entry points. Begin by locating the Kotlin SDK generator and its GSON and okhttp usage, then define the target-platform scope and migration plan; done means the SDK uses Kotlin Multiplatform with kotlinx.serialization and Ktor across the agreed targets.

Written by the indexing model from the issue text.