Investigate the possibility of returning an error instead of a panic when file is locked by another process

[ikopylov]

https://github.com/qoollo/pearl/blob/v0.18.0/src/blob/file.rs#L49

When an advisory lock cannot be acquired, the process panics. In general, in such cases it is better to return an error. But this can lead to the skipping of some files, which is incorrect. Normally, the error should propagate to the storage level and prevent it from being created/started. The possibility of such changes should be investigated