Grouped table generation for unified embedding

[Fiery]

Summary: Implementing feature grouping in APS model generator to enable unified embedding onbaording to FM

This diff introduced a new config section "unified_embedding" inside AdsFeatureArchEntityConfig and AdsFeatureArchConfig (for v1/v2 compatibility)

Major configurable properties enabled in this section is as below:

• features
  • {name: seeds}
• sharding
  • type
  • col_wise_shard_dim
• embedding_dim

There are other alternative to this design which has been thoroughly discussed in

Differential Revision: D58615622

[facebook-github-bot]

This pull request was exported from Phabricator. Differential Revision: D58615622