Make CamelRuntime smart to decide deferInitPhase

[ppalaga]

Currently, deferInitPhase true or false needs to be decided by the application developer depending on whether she wants to pass different config values to the app at runtime. However, the CamelRuntime could potentially be made smart enough to decide based on the available config values. E.g. {{env:AWS_ACCESS_KEY}} is a clear indicator of a runtime value.

cc @gnodet

[ppalaga]

@gnodet noted in a call that this is not going to get resolved with Camel 3.0.0. We agreed to keep using the manual deferInitPhase in the mean time, eventually switching its default to true because it more likely to give what the users expect.

[ppalaga]

Change the default

[ppalaga]

See #172