Abstract proguard rules at package level

[LuisDuarte1]

After some investigation on #1242, I've concluded that:

• javax.annotations has annotations included in the JSR305, which is a spec of annotations that help with IDEs or other tools to avoid software defects.
• com.google.errorprone has annotations related to ErrorProne, a static analyzer with its own set of annotations like above.

These annotations are not reflected at runtime in any shape or form so, it's safe to ignore them (unfortunately, libs cannot specify what to ignore or not on proguard, so we need to do this by hand).

This PR groups the two annotation packages.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 17%. Comparing base (3ab886a) to head (79694ec).

Additional details and impacted files

@@           Coverage Diff           @@
##           develop   #1247   +/-   ##
=======================================
+ Coverage       17%     17%   +1%     
=======================================
  Files          229     229           
  Lines         6965    6965           
=======================================
+ Hits          1149    1156    +7     
+ Misses        5816    5809    -7