loadConfigFile in launcher script doesn't support spaces in options.

Expected behaviour

If my application.ini file, loaded by the loadConfigFile contains arguments with a space in it, for example:

-J-XX:OnOutOfMemoryError=/usr/sbin/my-oom-handler arg1 arg2

then that line should be passed as a single argument to the command not as three separate arguments.

Actual behaviour

The option is split on space and printed passed as the equivalent of '-J-XX:OnOutOfMemoryError=/usr/sbin/my-oom-handler' arg1 arg2.

At the packaging stage, you can workaround it by using something like:

bashScriptExtraDefines ++= Seq(
  "addJava -XX:OnOutOfMemoryError='kill -9 %p'"
)

However, if you need to add such configuration after installing a deployed artifact (such as a deb package), the only workarounds I can find are to modify the launch script, or to pass the option on the command line. The first is undesireable because I don't want to change launch script that is managed by the deb package. The second is undesirable, because it requires changing the ExecStart line of the the systemd service.

Information

What sbt-native-packager are you using 1.5.2
What sbt version 1.5
What is your build system (e.g. Ubuntu, MacOS, Windows, Debian ) Ubuntu 20.04
What package are you building (e.g. docker, rpm, ...) deb
What version has your build tool (find out with e.g. rpm --version) dpkg 1.19.7
What is your target system (e.g. Ubuntu 16.04, CentOS 7) Ubuntu 20.04

suggested fix:

Instead of using $(loadConfigFile "$script_conf_file") directly [here](https://github.com/sbt/sbt-native-packager/blob/df35f5f39b015892e57069f566da1aae160e5517/src/main/resources/com/typesafe/sbt/packager/archetypes/scripts/bash-template#L356], first store it in array, with something like:

if [[ -f "$script_conf_file" ]]; then 
  IFS=$'\n' read -a -r -d '' config_options < <(loadConfigFile "$script_conf_file")
  set -- "${config_options[@]}" "$@"
fi

Or, alternatively, for the array readding line:

readarray -t config_options < <(loadConfigFile "$script_conf_file")

(mapfile is a synonym to readarray)

sbt / sbt-native-packager