Datepicker Component does not work inside modal that uses dialog tag

[ericenns]

Describe the bug A clear and concise description of what the bug is.

Attempting to use Datepicker inside of a modal which uses <dialog> tags, shows datepicker options underneath modal as they are appended to the body tag.

To Reproduce Steps to reproduce the behavior:

1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error

Expected behavior A clear and concise description of what you expected to happen.

Prior to 2.x this worked as one could pass the container option and specify the id of the <dialog> element.

Screenshots If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: [e.g. iOS]
• Browser [e.g. chrome, safari]
• Version [e.g. 22]

Smartphone (please complete the following information):

• Device: [e.g. iPhone6]
• OS: [e.g. iOS8.1]
• Browser [e.g. stock browser, safari]
• Version [e.g. 22]

Additional context Add any other context about the problem here.

Temporarily I have monkey patched the code within my application to enable use of the Datepicker within a dialog.

See https://github.com/phac-nml/irida-next/pull/859/files