Feature: Support AssertLog Test

[spacetj]

Description

Support the ability to assert the logs of a pod contains / not contains the string that you would expect it too.

Basic Example

The input would look something like:

- type: AssertLog
  spec:
    contains: "Some String"
    lines: 100  # Optionally provides the number of log lines to compare to
  resource:
    objectRef:
      type: Resource
      spec:
        kind: Pod
        namespace: applications
        labels:
          hello: world

Motivation

The Sealed Secrets controller will output a decryption error log if one of the sealed secrets isn't decrypted properly. anchorctl should be able to parse the logs and fail the test if the logs contain the phrase "Decryption error"