fix: Don't try to extract a non-existant zip file (#3668)
fix: Don't try to extract a non-existant zip file (#3668)

When the container is restarted (not re-created) it crashes because the WAR file has already been unzipped and removed.  Only try to explode the WAR file if it exists.

Also extract some commonly-used directories and files to variables for easier editing in the future.
dhis2/dhis2-core,dhis2/dhis2-core,msf-oca-his/dhis2-core,msf-oca-his/dhis2-core,hispindia/dhis2-Core,dhis2/dhis2-core,hispindia/dhis2-Core,hispindia/dhis2-Core,msf-oca-his/dhis2-core,dhis2/dhis2-core,hispindia/dhis2-Core,msf-oca-his/dhis2-core,hispindia/dhis2-Core,dhis2/dhis2-core,msf-oca-his/dhis2-core