Improve display element builders

[labkey-adam]

Rationale

Making our builders a bit easier to use:

• Code usually interacts directly with builders, so make the builders top-level classes for import convenience and make the display elements inner classes.
• Move all builder classes to the same package (org.labkey.api.util)
• Introduce LinkBuilder static factory methods simpleLink() and labkeyLink() for convenience
• Introduce InputBuilder static factory methods checkbox(), file(), hidden(), radio(), and text() for convenience
• Introduce JspBase.simpleLink()

[labkey-adam]

@bbimber see LinkBuilder.simpleLink() and other convenience methods introduced here. Better late than never...

[bbimber]

@bbimber see LinkBuilder.simpleLink() and other convenience methods introduced here. Better late than never...

Thank you! I think I had my fill of link refactoring for the time being, but am very glad to see it added. I'll also try to break my habit of over-using PageFlowUtil.

[labkey-jeckels]

Maybe we'll need a simpleLink(String, String) for some of my suggestions in other PRs. Probably worth it to get rid of more clearClasses()

[labkey-jeckels]

Is this intended for this PR? System.out.println()?

[labkey-adam]

Nope, unintentional. That snuck out of my "ignore" change list. Reverted.