[WIP][DAT-3394] Add support for maxcompute as source type (batch)

[vinoth-gojek]

This is WIP or draft MR.

The changes in MR are to enable MaxCompute as a datasource type for batch jobs (offline to online ingestion)

1. The MR adds the BATCH_MAXCOMPUTE enum
2. The changes in sdk enable clients to use maxcompute as source type
3. The spark override is intentionally left out and I will add it in the upcoming MRs

With these changes, record with batch_source maxcompute is added to the datasources table

postgres=> select * from data_sources;
42 | BATCH_MAXCOMPUTE | {"table_ref":"datasource:playground.dsp_maxcompute_dogfood"} | {} | created_timestamp | created_timestamp |