VMware: read network-config from ISO

[t-8ch]

Proposed Commit Message

There is no reason for the ISO missing this functionality.

As discussed in https://github.com/canonical/cloud-init/pull/947/files#r707338489

Test Steps

1. Create a ovf-env.xml which includes 'network-config' Property
2. Set 'network-config' Property's value to base64 encoded network config
3. Create OVF ISO containing ovf-env.xml
4. Verify cloud-init can get network config from OVF ISO

Checklist:

• My code follows the process laid out in the documentation
• I have updated or added any unit tests accordingly
• I have updated or added any documentation accordingly

Cc @PengpengSun

[TheRealFalcon]

@t-8ch , thanks for the PR.

I noticed you signed the CLA, but haven't yet added yourself to the CLA signers file. As part of this PR, please also add your name (alphabetically) to the CLA signers file. The full details are described in the last bullet point of the documentation.

[t-8ch]

@TheRealFalcon done

[TheRealFalcon]

hey @t-8ch ,we had a CI failure on main (unrelated to this code), so your branch needs to be rebased in order for CI to pass.

[t-8ch]

@TheRealFalcon done