Support Concurrency when executing conditional requests with payloads

[tarunKoyalwar]

Nuclei version:

main | latest

Proposed Changes:

• follow up of #5016
• this limitation is for cases where bruteforcing or sending multiple payloads while dynamic extracting some values , a good example is this extracting csrf token and using it while bruteforcing username - password combinations
• current limitation forces this to only happen sequentially but we can try to add a feature to support / implement concurreny in such conditions
• there are multiple ways to achieve this some of them are
  • adding option to tune generator behaviour and use two generators one for request iteration and another for payloads
  • support this at flow level ?
  • maybe handle this in new template workflow engine [ i mean concurrency ] ?

[tarunKoyalwar]

• temp fix is to limit threads value based on threshold https://github.com/projectdiscovery/nuclei/pull/4992