Simplify and provide default values in edit_mainconfig.php

jirikadlec2[CodePlex]
I suggest to simplify the quotsetupquot page (edit_mainconfig.php),
for example:

replace the UtcOffset and UtcOffset2 by one quotUTC Offsetquot textbox provide default value for the quotConfiguration settings for adding new sourcequot (quotISO 19115quot)
provide default value for spatial reference (WGS 84) provide default value for vertical datum, posaccuracy_m need better explanation for Time Support (it's not clear what the time time units are - probably minutes?)

Start by reviewing edit_mainconfig.php and the setup form it renders. Identify the UTC offset, source configuration, spatial reference, vertical datum, positional accuracy, and time-support fields, then verify that the requested simplification, defaults, and explanation are all visible and understandable on the setup page.

Written by the indexing model from the issue text.