Update init_ddp_connection logging info message and update function name

[four4fish]

Proposed refactoring or deprecation

init_ddp_connection is not only used by DDP, but also used by FSDP and other plugins inherit DDP. The log info and rank_zero_info saying ""initializing ddp" or "DDP processes", which could be confusing for user

Motivation

Debuggability and readability

Pitch

Update info message to be generic message
Update function name to initialize_distributed_connction as it's used by fsdp and sdp

Additional context

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[tchaton]

Good idea, let's do this