Factor out storage creation from SHM scripts

[craddm]

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⤴️ Summary

Moves the SHM storage account creation step into its own script, adds it as a step in the Deploy_SHM.ps1 script

🌂 Related issues

Closes #1366

🔬 Tests

Tested SHM deployment and storage account creation with new scripts.

[JimMadge]

Looks good, one comment about help text.

[craddm]

Looks good, one comment about help text.

I can't see any comments or changes requested

[JimMadge]

🤦