Implemented date time fields

[MichalRemis]

Implemented date/time inputs for Bootstrap4 configuration. (skipped plain SimpleForm because it is complicated - it doesn't have special wrapper for date/time fields and neither marks invalid fields 'is-invalid' when server side validating)

This PR requires https://github.com/DavyJonesLocker/client_side_validations/pull/784 and #81 to work. To make tests pass I included #81 commit in branch and required https://github.com/DavyJonesLocker/client_side_validations/pull/784 branch in Gemfile. Not sure if this is correct approach

[MichalRemis]

I suppose failing tests are because of missing https://github.com/DavyJonesLocker/client_side_validations/pull/784 in old gemfiles

[tagliala]

I suppose failing tests are because of missing DavyJonesLocker/client_side_validations#784 in old gemfiles

Yes, you should edit appraisals, as well as the travis configuration. Also, this change will work only on compatible versions of CSV, please ignore travis for the moment.

Also, I'm more interested in finishing CSV's side before this. I've a lot of concerns but at the moment I don't have time to elaborate (long story very short: javascript breaks the form removing html fields, should not happen)