Workspace argument name should be unified across all "az ml" commands ("--workspace-name")

### Extension name (the extension in question)
Machine Learning CLI extension version 1.0.10

### Description of issue (in as much detail as possible)

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Most `az ml` commands accept the Workspace name as argument. Unfortunately, the commands differ in the long form of the argument:

Argument long form|Command count|Example commands
------------------|-------------|----------------
--workspace-name|37|`az ml computetarget create aks`, `az ml image list`, `az ml service run`
--workspace|15|`az ml computetarget attach aks`, `az ml history info`, `az ml project attach`

This presents unnecessary difficulties for users who want to use the long arguments for clarity and maintainability of scripts.

All workspace name arguments should be unified to `--workspace-name`. This will not break existing scripts, because thanks to Azure CLI argument parsing rules `--workspace` will be matched to `--workspace-name`.