[Quick Fix] Add wait time between web scrapping requests

[davidgxue]

Description

• Context: See here ask_astro_load_astro_forum DAGs failing intermittently #262
• Note: this is a quick turnaround fix. Will need to look into better retry logic long term down the road and potentially write a wrapper for the requests.
• Added wait time between calls so we don't get 429 error when web scrapping in our DAGs.

Technical Changes

• Added timeout of 1 sec at a few spots
• Added user agent in requests header (see reason here)

Notes

• We can also do exponential backoff retry as an alternative if that route is preferred
  fixes ask_astro_load_astro_forum DAGs failing intermittently #262

[Lee-W]

should we use something like https://github.com/jd/tenacity? Not a blocker for now though.

[davidgxue]

Thanks @Lee-W for the suggestion and yes I agree. This will just be a quick turnaround fix for now so prod would have better stability. Long term probably use a mix of tenacity and implementation similar to this one https://github.com/alexwlchan/handling-http-429-with-tenacity. It's also probably better practice to create a requests client wrapper that auto retries for all of our requests.get calls. I will make an issue to track this