Add on-demand package data collection for nuget

[chinyeungli]

We want to enable the collect/ endpoint for nuget to avoid failure to collect a nuget PURL like pkg:nuget/newtonsoft.json@13.0.3 :

{
  "status": "cannot fetch Package data for pkg:nuget/newtonsoft.json@13.0.3: no available handler"
}

(https://www.nuget.org/packages/newtonsoft.json/)