refactor: move all shellcheck disable definitions to .shellcheckrc file

This makes standard use of shellcheck work without needing to provide extra configuration anywhere.

Also remove use of inline 'shellcheck disable' calls that are already defined in the .shellcheckrc and don't need to be set inline.

tests/ci/setup.sh

@@ -159,7 +159,6 @@ create_package() {
   build_dokku
 }
 
-# shellcheck disable=SC2120
 setup_circle() {
   install_dependencies
   install_dokku
@@ -188,12 +187,10 @@ case "$1" in
     run_dokku_container
     ;;
   build)
-    # shellcheck disable=SC2119
     create_package
     exit $?
     ;;
   *)
-    # shellcheck disable=SC2119
     setup_circle
     exit $?
     ;;

tests/ci/unit_test_runner.sh

@@ -21,7 +21,6 @@ is_number "$BATCH_NUM" || usage
 TESTS=$(find "$(dirname "$0")/../unit" -maxdepth 1 -name "${BATCH_NUM}0*.bats" | sort -n | xargs)
 echo "running the following tests $TESTS"
 
-# shellcheck disable=SC2086
 for test in $TESTS; do
   echo $test
   starttest=$(date +%s)