[controller] Allow restricting certain DatadogAgent features

[xornivore]

What does this PR do?

Introduces additional CLI options to allow restricting:

• DatadogAgent features, such as running system-probe container
• Container image registries
• Using specific host storage path for temp storage in logs agent.

Motivation

Better support for managed Kubernetes environments.

Additional Notes

Anything else we should know when reviewing?

Describe your test plan

Write there any instructions and details you may have to test your PR.

[codecov-io]

Codecov Report

Merging #238 (4aa09a0) into master (7eb3b98) will increase coverage by 0.11%. The diff coverage is 59.25%.

@@            Coverage Diff             @@
##           master     #238      +/-   ##
==========================================
+ Coverage   35.46%   35.58%   +0.11%     
==========================================
  Files          54       54              
  Lines        9290     9335      +45     
==========================================
+ Hits         3295     3322      +27     
- Misses       5753     5767      +14     
- Partials      242      246       +4     

Flag	Coverage Δ
unittests	35.58% <59.25%> (+0.11%)	:arrow_up:

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

Impacted Files	Coverage Δ
controllers/datadogagent/agent.go	55.78% <33.33%> (ø)
controllers/setup.go	63.15% <55.55%> (-3.51%)	:arrow_down:
controllers/datadogagent/controller.go	55.00% <58.82%> (+1.96%)	:arrow_up:
controllers/datadogagent/utils.go	82.74% <100.00%> (+0.04%)	:arrow_up:

---

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 7eb3b98...4aa09a0. Read the comment docs.