Allow javaArgs for all Zowe Java processes

[nigelvwilliams]

Customers who wish to monitor the JVMs in Zowe, say with OMEGAMON for JVM cannot easily add Java Arguments to the Java configuration.

Describe the experience you'd like
Currently only the Message Service JVM has a javaArgs yaml field. We'd like all the Java process to have that option.

Describe alternatives you've considered
Manually altering the template arguments, but they may get overwritten by maintenance.

[1000TurquoisePogs]

@balhar-jakub I'm going to move this over to api-layer as the biggest source of java, but, here's a thought to spark discussion:

Because there's many uses of java, let's continue following the sort of standardization pattern we recently did with things like networking.

Idea 1 - Object based YAML

If we assume all args implicitly have "-", it can be omitted and the object could look like:

java:
  args:
    Dkey: value

components:
  gateway:
    java:
      args:
        Dkey: override

Where, we have an object for global use, and then an override for a specific server use.
I guess you would need some shell scripting to convert the object into a string you can add to your java call.

Omitting "-" would be helpful because a YAML key starting with "-" could cause user error, parsing error, or env var error.

The object format could use some more thought for what is best.

Idea 2 - one big ugly string

java:
  args: "-Dkey0=value0 -Dkey1=value1"

In your code maybe it would look like

java \
  ${ZWE_configs_java_args:-${ZWE_java_args}} \
  # more args... \
  -jar "${JAR_FILE}"

[1000TurquoisePogs]

let me know what you come up with here because might want to do the same for nodejs.
Right now we have a one-off thing called ZWED_FLAGS but its undocumented.

[colinpaicemq]

z/OSMF has the following
JVM_OPTIONS="-Xoptionsfile=/global/zosmf/configuration/local_override.colin"
so have one yaml entry under java
optionsfile : .... name
That makes it easy to implement, and it is up to the user to provide and change the file.