azure-mgmt-*: re-init older versions for use with nixops

[bendlas]

add pinned versions package-private

azure-mgmt-compute 0.20.1
azure-mgmt-network 0.20.1
azure-mgmt-nspkg 1.0.0
azure-mgmt-resource 0.20.1
azure-mgmt-storage 0.20.0

replacement for #52550

Motivation for this change

nixops is incompatible with the most recent versions of listed
azure-mgmt-* packages, therefore we should pin them to
package-private versions, so that they don't get trampled by
updates, while NixOS/nixops#1065 is fixed.

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Assured whether relevant documentation is up to date
• Fits CONTRIBUTING.md.

---

[bendlas]

Actually, the updated builds for azure-mgmt-* are failing (in addition to nixops being incompatible with that release), so I'll merge this right away, in order to restore nixops to a working state. Instead, I'll re-open the PR, fixing the newer releases ...

[flokli]

backported to 19.03 in 17a5b64.

[tomberek]

This seems to work for nixopsUnstable as well.