Fixes and improvements to global ops functions in wbemcli.

Details:
- Removed long global function names (e.g. `EnumerateInstances`), and kept
  the short names (e.g. `ei`).
- Fixed missing `ns` parameter of `ci()`.
- Fixed incorrect invocation of underlying operation in several short
  functions:
  - `orip()` invoked `OpenReferenceInstances()`.
  - `oaip()` invoked `OpenAssociatorInstances()` and incorrectly had
    `iq`, `ico`, `pl` parameters.
- Fixed incorrect position of `rc` parameter in `oqi()` function.
- In `mc()`, removed returning the result of the underlying operation
  that doesn't return anything.
- Fixed errors in docstrings and improved the docstrings of the short
  functions.