MLCOMPUTE-951 | Refactor and make the spark_config modular (#118)

* MLCOMPUTE-699 | added mandatory spark defaults, deprecated mesos usage, refactor

* MLCOMPUTE-699 | removed hardcoded defaults and throw error if srv configs read fails

* MLCOMPUTE-699 | bump up version

* MLCOMPUTE-699 | add method signature

* MLCOMPUTE-699 | some more mesos deprecation

* MLCOMPUTE-699 | removed mesos tests, handle srv config file not present

* MLCOMPUTE-699 | refactor and modularise spark_config.py and fix tests

* MLCOMPUTE-951 | version bump up

* MLCOMPUTE-951 | use mock spark srv config in all tests

* MLCOMPUTE-951 | fix tests

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Co-authored-by: Sameer Sharma <[email protected]>

Author: CaptainSame