* new slog in stdlib is utilized for that and replaces 'log' pkg
* configuration pkg is used validate and now set/define/refer
  log level values
* the 'error' level call is not fatal, thus os.Exit is called
  instead

This is to improve/funnel potentially fatal errors

This is being handled by Fiber, hence not tested.

For now it's just ephemeral.

Instead of disabling the timeout (-1), it's set to 1 ms for all requests
in the state paths test. Otherwise race condistion may occur. Symptoms include
incorrect state name, because it may have been read before it's fully written
to the store.

* add dependency to allow limiting possible values, though actual
  validation doesnt happen yet
* make variable that indicates health local instead of global