Add container logs scraping from file by default

[vboulineau]

What does this PR do?

Align with the Helm chart. We are mounting pod logs host path and container logs host path.

Motivation

What inspired you to submit this pull request?

Additional Notes

Anything else we should know when reviewing?

[ahmed-mez]

LGTM but let's see why e2e tests fail before merging

[codecov-io]

Codecov Report

Merging #88 into master will increase coverage by 0.03%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master      #88      +/-   ##
==========================================
+ Coverage   57.40%   57.43%   +0.03%     
==========================================
  Files          31       31              
  Lines        4158     4161       +3     
==========================================
+ Hits         2387     2390       +3     
  Misses       1592     1592              
  Partials      179      179              

Flag	Coverage Δ
#unittests	57.43% <100.00%> (+0.03%)	⬆️

Impacted Files	Coverage Δ
pkg/controller/datadogagent/utils.go	83.33% <100.00%> (+0.05%)	⬆️

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[vboulineau]

LGTM but let's see why e2e tests fail before merging

Seems to be random failure, I cannot reproduce it and different runs do not yield the same failure.
I'm guessing it's due to:

2020-05-11 16:20:23 UTC | SYS-PROBE | CRITICAL | (cmd/system-probe/main.go:122 in main) | failed to create system probe: could not enable kprobe(kprobe/tcp_get_info) used for offset guessing: cannot write "p:ptcp_get_info tcp_get_info\n" to kprobe_events: write /sys/kernel/debug/tracing/kprobe_events: device or resource busy

But I'm not sure. I believe we could improve readability of e2e tests logs, I'll make another PR later for that.

[ahmed-mez]

Thanks for looking into it,