Split EmbraceImpl implementation into API delegates

[fractalwrench]

Goal

Splits the EmbraceImpl implementation so the user API is implemented as a delegate. Future changesets will factor other related APIs into appropriate delegates.

Testing

Added unit test coverage.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 22.22222% with 56 lines in your changes are missing coverage. Please review.

Project coverage is 80.78%. Comparing base (0131c8e) to head (6a0dfaf).

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #849      +/-   ##
==========================================
- Coverage   80.89%   80.78%   -0.12%     
==========================================
  Files         424      426       +2     
  Lines       11458    11464       +6     
  Branches     1748     1748              
==========================================
- Hits         9269     9261       -8     
- Misses       1433     1448      +15     
+ Partials      756      755       -1     

Files	Coverage Δ
.../android/embracesdk/injection/InjectEmbraceImpl.kt	100.00% <100.00%> (ø)
...embracesdk/internal/api/delegate/SdkCallChecker.kt	85.71% <85.71%> (ø)
.../java/io/embrace/android/embracesdk/EmbraceImpl.kt	61.23% <21.42%> (+6.16%)	:arrow_up:
...mbracesdk/internal/api/delegate/UserApiDelegate.kt	8.33% <8.33%> (ø)

... and 3 files with indirect coverage changes