New Command field in generated manifest

[#78294704]

Signed-off-by: Jonathan Berkhahn <jaberkha@us.ibm.com>
Includes startup command in `create-app-manifest`

[#78294704]

Signed-off-by: Jonathan Berkhahn <jaberkha@us.ibm.com>
Sort Environment Vars in manifest alphabetically

[#78294704]

Signed-off-by: Jonathan Berkhahn <jaberkha@us.ibm.com>
Preserve user-provided vars type when generating manifest.

[finishes #78294704]

Signed-off-by: Jonathan Berkhahn <jaberkha@us.ibm.com>