rollout controller find sourceRevision

[wangyikewxgm]

What this PR does / why we need it:

application use rollout as a trait, user shouldn't care sourceRevision.
when a new rollout restart, rollout controller use status.LastTtargetRevision as sourceRevision
application using rollout trait example is:

apiVersion: core.oam.dev/v1beta1
kind: Application
metadata:
  name: rollout-trait-test
  namespace: rollout-trait-test
spec:
  components:
    - name: express-server
      type: webservice
      properties:
        image: stefanprodan/podinfo:4.0.3
      traits:
        - type: rollout
          properties:
            targetSize: 5

Which issue(s) this PR fixes:

related issue: #1605

Special notes for your reviewer:

[codecov]

Codecov Report

Merging #1989 (9c554b4) into master (7161959) will increase coverage by 4.95%.
The diff coverage is 80.00%.

@@            Coverage Diff             @@
##           master    #1989      +/-   ##
==========================================
+ Coverage   59.09%   64.04%   +4.95%     
==========================================
  Files         111      159      +48     
  Lines       10998    14973    +3975     
==========================================
+ Hits         6499     9590    +3091     
- Misses       3804     4419     +615     
- Partials      695      964     +269     

Flag	Coverage Δ
e2e-rollout-tests	30.32% <80.00%> (?)
e2etests	38.12% <0.00%> (?)
unittests	59.26% <60.00%> (+0.17%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...ard.oam.dev/v1alpha1/rollout/rollout_controller.go	80.58% <50.00%> (+71.67%)	⬆️
...oller/standard.oam.dev/v1alpha1/rollout/handler.go	67.74% <100.00%> (+12.63%)	⬆️
pkg/workflow/tasks/custom/task.go	74.63% <0.00%> (-2.29%)	⬇️
pkg/utils/apply/apply.go	92.18% <0.00%> (-0.35%)	⬇️
...dev/v1alpha2/applicationconfiguration/component.go	59.05% <0.00%> (-0.30%)	⬇️
...rollout/workloads/deployment_rollout_controller.go	88.18% <0.00%> (ø)
...is/standard.oam.dev/v1alpha1/rollouttrait_types.go	20.00% <0.00%> (ø)
apis/core.oam.dev/v1alpha2/application_types.go	0.00% <0.00%> (ø)
apis/core.oam.dev/v1alpha1/envbinding_types.go	100.00% <0.00%> (ø)
pkg/appfile/config/configmap.go	0.00% <0.00%> (ø)
... and 110 more

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[wonderflow]

LGTM