EULAs now show up on the allocation detail page, and a manager is prompted to agree to a EULA when adding users to an allocation

[rg663]

Resolves part of issue #420 — Now, the EULA attribute value is displayed on the allocation detail page if the allocation has a resource with a EULA. In addition, when adding users to an allocation with a resource with EULA, either from the allocation detail page or from the project detail page, managers are prompted to agree to the EULA before completing the addition process.