[Feat]: Add parameter to struct for pushing block request for stopping scaling

[benjivesterby]

This should allow a caller to set the channel and then push to the channel to stop scaling and otherwise allow scaling. This will likely require a routine middle layer for translating a push to a stop to keep the scaler working normally.

[benjivesterby]

I'm not sure how I feel about this one. I'm going to test out the new scaling duration and max routine stuff before moving onto this.

The idea here was to allow an external user to push events over a channel to stop the scaling of go routines. This would allow for a user monitoring memory or cpu usage to halt scaling when exceeding some limit. It adds quite a bit of complexity as well as an additional backend goroutine and a select case with potential performance impact.

If the new additions for tuning are not sufficient then this may be necessary but for now I'm going to hold off on this.