Make search condition drop-down menu less unwieldy

[dstillman]

(In [1177]) Closes #346, mapping for new item types
Closes #227, Indent nested collections in search drop-down
Addresses #528, Make search condition drop-down menu less unwieldy

• Created new distinct fields for differently labeled fields
• Mapped lots of fields to base fields
• Made base field search conditions search type-specific fields as well
• Removed type-specific fields that are based on base fields not show up in search conditions drop-down
• Added a tooltip when hovering over a condition in the search conditions drop-down that shows the fields it searches (when there's more than one)
• Moved search dialog CSS to separate file

[dstillman]

Milestone 2.0 Beta 3 deleted