Emitting events in Filestorage

[PolinaKiporenko]

For File storage UI, we need to display file timestamps. Now there are difficulties with displaying time stamps in UI due to in the file storage contract we don’t save the time stamp field and don’t emit this event.

Solution: Emit event in all functions which modify the state: createFile createDirectory deleteFile ...

[DmytroNazarenko]

We can add timestamps to ContentInfo struct: https://github.com/skalenetwork/filestorage/blob/develop/contracts/FileStorage.sol#L44

[gannakulikova]

@cstrangedk @christineRPM @ebruoguzberk the question from @DmytroNazarenko is still pending and is blocking further implementation: should we save a timestamp in smart contracts? Thank you

[cstrangedk]

move to 2.2 release