Updating APEX base image from policy-jre-alpine to policy-jdk-alpine

Updating APEX base image from policy-jre-alpine to policy-jdk-alpine

The stackoverflow issue is happening only in standalone mode when
RestManager class is called from APEX Javascript logic to post a
JSON body, that too 6-7 out of 10 times.
To identify the exact root cause may need more investigation,
but changing the base image from policy-jre-alpine to policy-jdk-alpine
seems to have fixed the issue during local testing.
(Issue didn't happen 10 out of 10 times)

Change-Id: Ibe718294ff9ab04c70349b3bc52c3c66619f2093
Issue-ID: POLICY-3066
Signed-off-by: a.sreekumar <ajith.sreekumar@bell.ca>