[refactor](load) Support loader with copy into

[smallhibiscus]

Proposed changes

In order to adapt the scenario of Doris storage and calculation separation , introduce copy_into load way with sink.load.mode (default stream_load).
The copy_into import method is divided into two stages:

1. First upload the data to object storage.
2. Then load the data on the object storage into Doris.

This import method is usually used for synchronization across vpc scenarios.

Problem Summary:

Describe the overview of changes.

Checklist(Required)

1. Does it affect the original behavior: (Yes/No/I Don't know)
2. Has unit tests been added: (Yes/No/No Need)
3. Has document been added or modified: (Yes/No/No Need)
4. Does it need to update dependencies: (Yes/No)
5. Are there any changes that cannot be rolled back: (Yes/No)

Further comments

If this is a relatively large or complex change, kick off the discussion at dev@doris.apache.org by explaining why you chose the solution you did and what alternatives you considered, etc...

[smallhibiscus]

@JNSimba @gnehil

[JNSimba]

LGTM