Add Error/Debug describers

[alexeev-igor]

I guess error/debug messages (like https://github.com/TinkoffCreditSystems/Horarium/blob/master/src/Horarium/Handlers/ExecutorJob.cs#L141 https://github.com/TinkoffCreditSystems/Horarium/blob/master/src/Horarium/Handlers/ExecutorJob.cs#L105 ) should be replaced with interface IErrorDescriber/IDebugDescriber with same methods instead of hard code them. Something like that:

string CreateJobError(string type) => $"Ошибка создания джоба {type}"