Log problem in layer and exit when agent image is not found

[t4lz]

Currently, if you override the default agent image with one that does not exist (e.g. -i test when running in the cloud and test only exists locally), then the created agent pod has statusImagePullBackOff and mirrord continues running locally. Instead, it should log an error and exit.

[thedanvail]

I'll start taking a look at this. CC @infiniteregrets

[KenCox94]

I would like to tackle this

[infiniteregrets]

@KenCox94 you got it, let me know if you need any help or join our discord https://discord.com/invite/metalbear