Add more date utility functions

[drebrez]

• Function to check if a string is an ISO date (example: https://github.com/neolution-ch/neolution-dotnet-templates/blob/main/templates/neo-react/Whitelabel.React.UI.Client/src/axios/interceptors/response/dates.ts#L3C1-L10C2)
• Function for reviving an ISO date inside a JSON (example: https://github.com/neolution-ch/react-hook-form-components/blob/main/src/lib/helpers/dateUtils.ts#L1-L12)
• toLocalISOString (https://github.com/microsoft/vscode/blob/main/src/vs/base/common/date.ts#L233)
• more date-fns utility functions (addDays, addMonths, addYears, clamp, ....)