Add resource limits to the "wavefront" deployment.

[dmaze]

Description

Adds resources: configuration to the adapter deployment object, both requests: and limits: 500m cpu and 256Mi memory. This provides some protection against the adapter pods getting evicted in a busy cluster.

Additional context

Our Wavefront-Istio adapter was getting frequently evicted from the cluster. #79 has an actual fix (the resource that was actually getting exceeded was "ephemeral storage", or local container filesystem space used up by logs) but adding resource constraints seems like generally good practice.