Disable warning as errors locally

[xgouchet]

What does this PR do?

Use the CI environment variable to enable the "show warning as errors" in Kotlin compiler

Motivation

During development, especially when doing TDD, I often find myself having variables/parameters temporarily unused, which prevent from running the tests.
This new option allows me to to TDD without manually changing the allWarningsAsErrors and still keep checks in the CI.

Note

The local_ci.sh script will set the environnement variable to ensure one can detect those warnings before pushing to CI

[codecov-commenter]

Codecov Report

Merging #1664 (42dfa24) into develop (a340c76) will decrease coverage by 0.11%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop    #1664      +/-   ##
===========================================
- Coverage    83.64%   83.53%   -0.11%     
===========================================
  Files          458      458              
  Lines        15767    15764       -3     
  Branches      2354     2353       -1     
===========================================
- Hits         13187    13167      -20     
- Misses        1946     1969      +23     
+ Partials       634      628       -6     

see 18 files with indirect coverage changes