* refactor: moved loading to new module
* refactor: check_single_separator
* refactor: simplified separator fixing
* refactor: tests/ -> lua/tests/
* refactor: moved to nvim_err_writeln for errors
* feat: moved config parsing to config.lua
* feat: get config directly from config module
* feat: added load_all function
* tests: config parsing tests
* added assert to luacheck globals
