Move 'main_class' and 'java_opts' into edp.java configs

Partial-implements: blueprint edp-config-parameter-prefix
Change-Id: I877ad30c97cd3e0741fc2bd3ef28333fb6eacc0a
Update the edp user doc to discuss "edp." configs for Java jobs

Parial-implements: blueprint edp-config-parameter-prefix
Change-Id: Ib416bd9d6daf255ab2c125c3617c5372874386e9
Modify the REST doc to show a Java job type execution

Hightight the special use of "edp.java.main_class"

blueprint edp-config-parameter-prefi
Change-Id: I2f82c1ac63b021bac39edf7d29ef47d6f7476768
Merge "Move 'main_class' and 'java_opts' into edp.java configs"
Merge "Update the edp user doc to discuss "edp." configs for Java jobs"
Merge "Modify the REST doc to show a Java job type execution"