Add a migration guide from Pandas

[zaleslaw]

as it added here https://ktor.io/docs/migration-from-express-js.html or here in Polars https://docs.pola.rs/user-guide/migration/pandas/#express-yourself with explanation of difference

Could be based on https://tech.dentsusoken.com/entry/kotlin_dataframe
Also, worth to refer for users on the OSS repos with migration guides from Python to Kotlin

https://github.com/Khan/kotlin-for-python-developers
https://kotlin-for-python.readthedocs.io/en/latest/