Feature: concurrently generate technical and behavorial questions

[hxu296]

Issue Description:

Currently, generating technical and behavioral questions takes approximately 35 seconds to complete. This extended duration to generate questions can negatively impact the user experience, as users might not be willing to wait that long for the results. To address this performance issue, I suggest implementing a concurrent generation process for technical and behavioral questions, which would potentially reduce the generation time to under 20 seconds.