feat: Add configurable liveness probe timeout

[bnaul]

Fixes #917

Plain helm install:

Liveness:      http-get http://:8080/healthz delay=0s timeout=1s period=10s #success=1 #failure=3

With --set livenessProbe.timeoutSeconds=5:

Liveness:      http-get http://:8080/healthz delay=0s timeout=5s period=10s #success=1 #failure=3

[bnaul]

@jacobtomlinson I would probably say bump the default but no strong preference, figured I'd start with the same value and just make it configurable

Suggested change

	timeoutSeconds: 1
	timeoutSeconds: 5

[jacobtomlinson]

This looks great! Happy to bump the default value.

[jacobtomlinson]

Hmm it won't let me commit the suggestion to change it to 5. Could you update the PR?

[bnaul]

@jacobtomlinson done, plus updated the README

[jacobtomlinson]

Perfect thank you!