ResetCommand should not wipe out all configs

Currently, ResetCommand clear all configurations, including sql configs, static sql configs and spark context level configs.
for example:
```
spark-sql> set xyz=abc;
xyz abc
spark-sql> set;
spark.app.id local-1585055396930
spark.app.name SparkSQL::10.242.189.214
spark.driver.host 10.242.189.214
spark.driver.port 65094
spark.executor.id driver
spark.jars
spark.master local[*]
spark.sql.catalogImplementation hive
spark.sql.hive.version 1.2.1
spark.submit.deployMode client
xyz abc
spark-sql> reset;
spark-sql> set;
spark-sql> set spark.sql.hive.version;
spark.sql.hive.version 1.2.1
spark-sql> set spark.app.id;
spark.app.id <undefined>
```