Clearing any nuget configuration that might be coming from parent dir…

[martinchrzan]

…ectories, fixes #4595

Summary of the Pull Request

Clearing any nuget configuration that might be coming from parent directories. Setting global cache for nuget packages causes overriding our local nuget references and preventing solution build from working.
Adding project level nuget.config which overrides any unwanted parent config.

References

PR Checklist

• Applies to Nuget restore and build fails  #4595
• CLA signed. If not, go over here and sign the CLA
• Tests added/passed
• Requires documentation to be updated
• I've discussed this with core contributors already. If not checked, I'm ready to accept this work might be rejected in favor of a different grand plan. Issue number where discussion took place: #xxx

Detailed Description of the Pull Request / Additional comments

Validation Steps Performed

I wasn't able to build the project before this change, now it builds successfully.

[enricogior]

LGTM

[enricogior]

@martinchrzan-mfst
for future reference, we use "Squash and merge" as primary option, "Rebase and merge" as second option.