Add notes on workspace VM sizes

[JimMadge]

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:vertical_traffic_light: Depends on

:arrow_heading_up: Summary

Add some useful notes to the deploy documentation about workspace VM sizes,

• Memory requirements of ClamAV
• CPU architecture
• GPU sizes
• Naming conventions (in particular for premium storage)
• Recommended starting points

:closed_umbrella: Related issues

Closes #1724

:microscope: Tests

[github-actions[bot]]

Coverage report

This PR does not seem to contain any modification to coverable code.

[JimMadge]

Thanks @craddm. I've made those changes and adjusted the wording a little after coming back with fresh eyes.