Introduce AuronExtFunctions

[Tartarus0zm]

it‘s a subtask of #1263
Currently, all extension functions in Auron are designed for Spark, Therefore, it is named SparkExtFunctions.
We are advancing multi-engine support for Auron, so the name SparkExtFunctions no longer meets our requirements.
Therefore, I suggest rename it to AuronExtFunctions.
Function Names for Native Implementations, I recommend using the following rules:

• If it's only used by Auron and not integrated with other engines, then use standard naming conventions, such as Placeholder;
• if used for spark should be start with 'Spark_', such as Spark_Murmur3Hash;
• if used for flink should be start with 'Flink_', such as Flink_UNIX_TIMESTAMP;
• same to other engines.