Consider renaming PFM module name

[gjermundgaraba]

The PFM module name has a spelling mistake in it.

Before we fix that, we need to consider the implications of renaming the module for chains that already integrate the ibc-apps version of the module (i.e. a chain that already has the module integrated with the wrong name).

Ref: #8285 (comment)_

[gjermundgaraba]

Need to verify this, but I believe the implications would be:

1. They would need an upgrade handler that removes the existing module and re-adds the existing one (would need to verify that we can do this without deleting all the existing state associated with the module, in which case we would need to add the module first and run a migration of the state)
2. Existing state would need to be migrated (is this even possible in a regular in-store migration given that the store prefix for the module has changed?)

[damiannolan]

This may help rename the iavl tree without needing kv state migrations.
https://github.com/cosmos/cosmos-sdk/blob/main/store/types/store.go#L77-L83

[gjermundgaraba]

That looks super useful! Thanks @damiannolan 🙏