feat: expose process_attachments for unstructured-ingest CLI

[ryannikolaidis]

Is your feature request related to a problem? Please describe.
When a connector partitions an email file the caller should be able to specify whether or not to process attachments, this should be exposed via the unstructured-ingest CLI.

Describe the solution you'd like
Most likely the PartitionConfig should passthrough a process_attachments argument

Describe alternatives you've considered
NA

Additional context
NA

[l4b4r4b4b4]

Would be highly appreciated!

[ahmetmeleq]

Another request: https://unstructuredw-kbe4326.slack.com/archives/C044N0YV08G/p1704731615678209