### What problem does this PR solve?
Implement Create/Drop Index/Metadata index in GO
New API handling in GO:
POST/kb/index
DELETE /kb/index
POST /tenant/doc_meta_index
DELETE /tenant/doc_meta_index
CREATE INDEX FOR DATASET 'dataset_name' VECTOR_SIZE 1024;
DROP INDEX FOR DATASET 'dataset_name';
CREATE INDEX DOC_META;
DROP INDEX DOC_META;
### Type of change
- [x] Refactoring
### What problem does this PR solve?
Go cli
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
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Signed-off-by: Jin Hai <haijin.chn@gmail.com>
