feat(configLoader): add cosmiconfig support

Added cosmiconfig support;
Added json5 support for configs;
Removed deprecated czConfig attribute support;
Added load and loadAtRoot public api hepers;
Removed findup and config normalization functions that are not required for now;

BREAKING CHANGE: config.path now resolves relative to config location;
  config lookup now relays on cosmiconfig search rules;
Closes: commitizen#773

.gitignore

@@ -6,4 +6,5 @@ artifacts/
 npm-debug.log
 .nyc_output
 test/tools/trigger-appveyor-tests.sh
-logo/*.png
+logo/*.png
+.idea