Add retry with delay on some errors

[legioner0]

Implements retry with delay in case if Icinga2 server returns 503 Icinga is reloading or low-level errors, like Connection refused.

[dakota-marshall]

Hey there! This repo hasn't seen activity in over 4 years, I think it's safe to say this project has probably been abandoned.

I'm not sure if this is bad manners or not, but I have been working on this repo for a month or so by adding support for the package config management endpoint to add support for Zone and Endpoint objects over on my fork dakota-marshall/go-icinga2-api. I also implemented the fix for creating host variables that I have waiting to merge in here. My goal is to try and pitch that the downstream Terraform provider switch to my repo eventually, so I can implement these updates and improvements can be made to the provider.

I'd love to have you merge your changes in over there if you're interested? This was actually on my todo list lol.

[legioner0]

Hello. Nice to hear that someone, except me, try to enhance terraform-provider-icinga2.

Sure. I'll made a PR to your fork.