[Enhancement] Support to map a subset of StarRocks columns to Flink source table

[banmoy]

What type of PR is this：

• [ ] BugFix
• [ ] Feature
• [x] Enhancement
• [ ] Refactor
• [ ] UT
• [ ] Doc
• [ ] Tool

Which issues of this PR fixes ：

Fixes # Currently columns between Flink schema and StarRocks schema must be same. It's not easy to use if the StarRocks table has thousands of columns, but the user only wants to read some columns of it. This PR supports to define the Flink source table only with some columns of StarRocks table that need to read. For example, StarRocks schema

CREATE TABLE t (
    c0 INT,
    c1 FLOAT,
    c3 STRING
);

If you just want to read c0 and c3, you can define flink source table as follows. Before this PR, must include all columns

CREATE TABLE t (
    c0 INT,
    c3 STRING
) WITH (
  ......
)

Problem Summary(Required) ：

Checklist:

• [x] I have added test cases for my bug fix or my new feature
• [ ] This pr will affect users' behaviors
• [ ] This pr needs user documentation (for new or modified features or behaviors)
• [ ] I have added documentation for my new feature or new function