rename chectl-based CLI tool to dsc for `Dev Spaces control`

Since CRW is no longer the appropriate acronym for RH OS Dev Spaces, we need a new name for the chectl-based CLI.

Based on 5:1 poll results, the choice is `dsc` (akin to `oc`).

Fabrice said:

The ctl suffix makes sense upstream because it references to kubectl. But not downstream where oc replaces kubectl. Therefore the `c` makes sense in terms of ecosystem naming consistency.