Track changes in ConfigMaps and Secrets

[stefanprodan]

This PR adds support for tracking ConfigMaps and Secrets referenced by a canary deployment:

• scan target deployment volumes and containers for configs and secrets
• create primary configs and secrets at bootstrap
• detect changes in configs or secrets and trigger a new canary rollout
• restart analysis if configs or secrets changed during rollout
• copy configs from canary to primary and update the pod spec annotations on promotion

Fix: #36

[codecov-io]

Codecov Report

Merging #37 into master will increase coverage by 3.23%.
The diff coverage is 69.39%.

@@            Coverage Diff             @@
##           master      #37      +/-   ##
==========================================
+ Coverage   53.52%   56.75%   +3.23%     
==========================================
  Files           8        9       +1     
  Lines        1035     1302     +267     
==========================================
+ Hits          554      739     +185     
- Misses        384      436      +52     
- Partials       97      127      +30

Impacted Files	Coverage Δ
pkg/controller/controller.go	6.7% <0%> (-0.22%)	⬇️
pkg/controller/deployer.go	59.28% <51.92%> (-2.55%)	⬇️
pkg/controller/scheduler.go	39.73% <54.54%> (+0.62%)	⬆️
pkg/controller/tracker.go	76.05% <76.05%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update b8a7ea8...4bcf82d. Read the comment docs.