`ENSO_JVM_OPTS` changes its meaning depending on `jvm` mode

[JaroslavTulach]

Originally posted by @JaroslavTulach in #13256 (comment)

• ENSO_JVM_OPTS environment variable is changing its meaning completely in non-JVM and --jvm mode
• e.g. there is no way to set ENSO_JVM_OPTS to non-trivial value that would work in both modes
  • for example -ea is valid in JVM mode, but not in native mode
• the JVM mode is also controlled by jvm: true in the package.yaml
• as such we can end up in a situation where users set ENSO_JVM_OPTS and then they can open just some of their projects

Goal

• design a solution that allows one to change the options project-manager sends to enso
• that works with and without JVM mode of enso
• verify it works with and without --jvm mode option of project-manager and enso executables
• verify it works with and without jvm: true flag in package.yaml of projects being open

[JaroslavTulach]

From the product perspective we'd prefer to:

• have a memory setting in project's package.yaml
• Q: how that's going to work from CLI? When enso is already running...

[JaroslavTulach]

The primary problem manifests itself when:

ENSO_LAUNCHER=native sbt
sbt:enso> buildEngineDistribution
sbt:enso> runProjectManager --debug

and listening in the IDE for the started enso engine process to connect to the debugger.

[JaroslavTulach]

From the product perspective we'd prefer to:
* have a memory setting in project's package.yaml

• that tracked as Memory settings in package.yaml #13294
• ENSO_JVM_OPTS shall only be needed for development
• and that works since Don't specify -ea when invoking runProjectManagerDistribution #13481