[INLONG-10942][SDK] Add official function names for all Transform functions

[Zkplo]

Fixes #10942

Motivation

Added official SQL functions for DateExtractFunction, FromUnixTimeFunction, SubstringFunction, and TimestampAdFunction classes

Verifying this change

(Please pick either of the following options)

• This change is a trivial rework/code cleanup without any test coverage.

• This change is already covered by existing tests, such as:
  (please describe tests)

• This change added tests and can be verified as follows:

  (example:)

  • Added integration tests for end-to-end deployment with large payloads (10MB)
  • Extended integration test for recovery after broker failure

[aloyszhang]

Is there any specifications for "official function names"？

[Zkplo]

Is there any specifications for "official function names"？“官方函数名称”有什么规范吗？

The official function name refers to the built-in function name defined in SQL, such as the dayofmont() function. When writing the function of inlong transform, due to readability, the function name may be defined as day_of_month. However, because it is inconsistent with the dayofmonth function name, it may cause difficulties for the caller to use it. Therefore, it is necessary to add an alias that is consistent with dayofmonth, so that the caller can call the function using both day_of_month and dayofmonth.