Move REQUIRE_CLIENT_AUTH code to start script

Move the conversion from the REQUIRE_CLIENT_AUTH env variable to the
Spring setting server.ssl.client-auth out of the Java code and in to the
start script. This declutters the code and exposes this setting.

Refactor the code for readability: have Jetty deobfuscate the password
string for us rather than manually detecting the "OBF:" prefix.

Also fix a typo (spelling mistake).

Change-Id: Ic670c04f97f59e06e48ca2cf4d7a0188020b3eaa
Issue-ID: AAI-2280
Signed-off-by: mark.j.leonard <mark.j.leonard@gmail.com>