Move packages out of pkg to root

[owais]

• Moved /pkg/factories and /pkg/configv2 to /factories and /configv2
  respectively.
• Moved /pkg/configmodels to /models

Discussed here: #69

[codecov-io]

Codecov Report

Merging #73 into master will not change coverage.
The diff coverage is 95.58%.

@@           Coverage Diff           @@
##           master      #73   +/-   ##
=======================================
  Coverage   71.37%   71.37%           
=======================================
  Files          91       91           
  Lines        6022     6022           
=======================================
  Hits         4298     4298           
  Misses       1500     1500           
  Partials      224      224

Impacted Files	Coverage Δ
receiver/jaegerreceiver/config.go	50% <ø> (ø)	⬆️
factories/factories.go	100% <ø> (ø)
models/configmodels.go	0% <ø> (ø)
cmd/occollector/app/collector/collector.go	79.26% <ø> (ø)	⬆️
receiver/jaegerreceiver/factory.go	100% <100%> (ø)	⬆️
receiver/prometheusreceiver/factory.go	72.09% <100%> (ø)	⬆️
configv2/configv2.go	98.64% <100%> (ø)
cmd/occollector/app/builder/receivers_builder.go	85.18% <100%> (ø)	⬆️
exporter/opencensusexporter/factory.go	87.32% <100%> (ø)	⬆️
receiver/opencensusreceiver/factory.go	82.35% <100%> (ø)	⬆️
... and 8 more

---

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[tigrannajaryan]

Can we use /config instead of /configv2?

[owais]

Took a quick look and don't why not but it'll need more careful update as quite a few files are using config as an identifier. If we can live with configv2 for now, I'll try to spend some time cleaning up and moving to config may be next week.

[bogdandrutu]

@tigrannajaryan that can be done in a separate PR. I would like to keep the PRs very granular.

[tigrannajaryan]

LGTM

[songy23]

Agree config vs. configv2 can be addressed in a separate PR.