Since the proxystore.connectors.dim requires a lot of special care for testing due to limitations of the Mochi/UCX dependencies, I've decided let's move that module to the proxystore-extensions package. PR #293 already warns users that the module may be moved, so let's target ProxyStore v0.6 for that migration.

Checklist:

• Updating the CI/docs/configs/etc. of proxystore-extensions to match that of ProxyStore (they are a bit out of sync now).
• Removing proxystore.connectors.dim from proxystore.
  • The module iteself
  • Test fixtures/imports/mocks
  • Tox recipe
  • CI workflows
  • Documentation references
  • Package extra installs
• Adding the code to proxystore-extensions.
• Move related issues from the main repository to the extensions repository.
• Releasing v0.1.0 of proxystore-extensions.
• Updating the benchmarks to depend on the proxystore-extensions package.