fix: increase timeout rate of lora metadata/model downloads

[tazlin]

The new multiprocess worker paradigm is very sensitive to timing in certain respects. This PR seeks to address the tendency for LoRa metadata or model downloads to get hung up at certain points in the model manager, which tends to lead to the worker detecting the working process as stale and leading to all sorts of issues.

In short:

• Adjusts timeouts to be more in line with real-time generation expectations as is the case with the worker.
• Gives up metadata collection sooner in certain probably unrecoverable circumstances, such as getting a 500 or HTML doc back.
• Increases the number of download threads to improve the chances that things move along
  • During testing, this is has been increased to 5x the previous number which greatly increases the rate at which LoRa based tests run.
• Increasing the polling frequency of threads (THREAD_WAIT_TIME)
• Binds several other time.sleep(...) calls to the value of THREAD_WAIT_TIME.

[db0]

Looks OK, my comment is more than I don't think increasing the threads would do much, but it won't hurt.