SNOW-1824418: Enable setting properties in the RuntimeConf / session.conf object for migration scenarions

[sfc-gh-mrojas]

What is the current behavior?

Currently session.conf can only set actual properties, but in spark the conf object can be used as a dictionary to hold program settings

What is the desired behavior?

when session.conf.compatibility_mode = True allow setting/getting random properties

How would this improve snowflake-snowpark-python?

This will ease migration scenarios from spark code.

References, Other Background

https://spark.apache.org/docs/latest/api/java/org/apache/spark/SparkConf.html#set-java.lang.String-java.lang.String-