Fix date equals filtering

[martmull]

Filtering on dates does not work:

filter: { and: [{createdAt: {eq: '2023-07-14T15:09:17.679Z'}}]} returns 0 values even if such a record exists in the db

[charlesBochet]

Input from @magrinj: scalar might not be represented correctly in graphql

[FelixMalfait]

Filtering seems to be expecting seconds/minutes/hours while most of the time we want to compare YMD.

Probably something to clarify around DATE vs DATETIME field, and make sure that even if DATETIME the filter only compares YmD

[FelixMalfait]

Equal date filtering was removed from DateTime field on the ui, we kept greater than / lesser than only We will introduce a Date field soon (no time), which should support equal filtering