[Improvement](multi catalog) The interface of external scan provide. WIP

[Jibing-Li]

This is the interface of external scan provide. For now, only define one method getSplits which is used by external table scan provide to get the splits for the scan node. For example, HMS, ES and so on.

In the future, will add more methods to this interface.

Checklist(Required)

• [ ] Does it affect the original behavior
• [ ] Has unit tests been added
• [ ] Has document been added or modified
• [ ] Does it need to update dependencies
• [ ] Is this PR support rollback (If NO, please explain WHY)

Further comments

If this is a relatively large or complex change, kick off the discussion at [email protected] by explaining why you chose the solution you did and what alternatives you considered, etc...

[Jibing-Li]

run buildall

[Jibing-Li]

run buildall

[Jibing-Li]

run buildall

[Jibing-Li]

run buildall