Update PoseEstimatorModule, AssetDatabase

[gilwoolee]

This PR contains the following updates:

• Update PoseEstimatorModule to follow c++ naming convention
• Have DELETE marker to be handled earlier (so that it doesn't look for matching assetKey but only checks for existing objectUid in world)
• Remove objectName from AssetDatabase since this information is already given by the marker (further, it removes the need for pr_assets to have different name for objects of same shape, e.g. cans or food items). Right now all tags either not have objectName or have objectName same as asset key.

---

Before creating a pull request

• Document new methods and classes
• Format code with make format

Before merging a pull request

• Set version target by selecting a milestone on the right side
• Summarize this change in CHANGELOG.md
• Add unit test(s) for this change

[egordon]

One substantial change, a couple of comment nits.

[codecov]

Codecov Report

Merging #508 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #508   +/-   ##
=======================================
  Coverage   77.69%   77.69%           
=======================================
  Files         262      262           
  Lines        6792     6792           
=======================================
  Hits         5277     5277           
  Misses       1515     1515

[brianhou]

Left some nit comments, but generally looks good to me.

[brianhou]

One last nit about DetectedObject-impl.hpp.