chore: do not depend on default for "fail-on-threshold"

fix default for fail-on-threshold

• feat: add flag to determine whether to fail on threshold

feat: do not fail if threshold was not reached

first tests for seperate mode flags, documentation will follow

fix: set default threshold to 0.05

fix: comparsion for lower than 0.01 (build)

feat: let action fail if coverage decreases by threshold