LP1834662: Various fixes to the datetime select

LP1834662: Various fixes to the datetime select

* Adds the caret specifier to package.json and bumps up the version of
moment-timezone
* Adds an example of the egValidDatetime directive
* Makes the makeFormatParseable function localizable
* Gets rid of an error when this component is used without ngModel or
reactive forms
* Fixes various linting errors
* Closes the datetimepicker if the user opens another datetimepicker

Signed-off-by: Jane Sandberg <sandbej@linnbenton.edu>
Signed-off-by: Bill Erickson <berickxx@gmail.com>