Stream logs from kube-task

[tdmanv]

Change Overview

• Prints logs from kube task pod as soon as they're ready in the controller
• Fixes some issues with WaitForPod* hanging

Issues

• Continuous logs from spawned commands #231

Pull request type

Please check the type of change your PR introduces:

• Work in Progress
• Refactoring (no functional changes, no api changes)
• Trival/Minor
• Bugfix
• Feature
• Documentation

Test Plan

[20:11:15]tom@tom-XPS-13-9360: (stream-log)~/src/kanister/pkg/function/ go test -v -check.v -check.f TestKubeTask
=== RUN   Test
INFO[0004] Pod: kanister-job-pstjh Container: container Out: ###Phase-output###: {"key":"version","value":"0.20.0"}
INFO[0015] Pod: kanister-job-w5bl2 Container: container Out: Tick: 1
INFO[0018] Pod: kanister-job-w5bl2 Container: container Out: Tick: 2
INFO[0018] Pod: kanister-job-w5bl2 Container: container Out: Tick: 3
PASS: kube_task_test.go:108: KubeTaskSuite.TestKubeTask 21.055s
OK: 1 passed
--- PASS: Test (21.12s)
PASS
ok      github.com/kanisterio/kanister/pkg/function     21.147s

• Manual
• Unit test
• E2E