Deprecate the `ibc-primitives` crate

[seanchen1991]

Feature Summary

As mentioned in this comment, the types that live under ibc-primitives are mostly host-related utilities that would be more appropriate living under the ics24-host crate.

Additionally, the boundary of what should and should not be included in ibc-primitives is not clear. As a result, we should consider deprecating the ibc-primitives crate and finding appropriate workspaces for its types to reside in.

Proposal

• Deprecate the ibc-primitives crate