test: methods for replacing forbidden chars

docs: add codefactor badge

ci(codecov): specify correct go version

docs: add details about is binary functions

test(write_all): add tests for RemoveAllIfExists

docs: add badges

ci: upload coverage with secret token

ci: add codecov action

docs: add readme

chore: add license

test(exist): test assertive analogues of exists funcs

test(string): add test for function WriteString

ci: specify used go version

fix: specify correct go version format

ci: setup testing pipeline

test: add tests for func Must

chore: initial commit