StdSysPropLoader & StdEnvVarLoader should trim String values

[eeverman]

Describe the bug
System properties and environment vars are typically set in configuration files. Why would these not be trimmed?

This refers to these two methods:

• StdEnvVarLoader.isTrimmingRequiredForStringValues
• StdSysPropLoader.isTrimmingRequiredForStringValues

Its likely that changing these defaults will not result in any tests breaking, but it should - tests should be added that verify the behavior.

[eeverman]

After changing this behavior, 31 (!) tests failed! That is good - it means the loader behavior is well tested (if not overly tested)

[eeverman]

Fixed by #688