Summary: Adapty adds Kotlin Multiplatform SDK

Why It Matters: This change shows Adapty is supporting more ways for developers to build apps.

What Changed:

• "KMP" changed to "Kotlin Multiplatform" in the "Mobile SDK" product menu.
• "KMP" changed to "Kotlin Multiplatform" in the "Mobile SDK" documentation menu.
• "KMP SDK" changed to "Kotlin Multiplatform" in the "Get the SDK for your platform" section.
• The "Ebook App Growth Playbook" link text changed to "Ebook $100K playbook | download".