Retain b2biAPI Liberty server.xml customisation during upgrades

During each upgrade of B2Bi (SFG), the b2biAPI package must be reinstalled using the InstallService script. This is typically performed immediately after the core product upgrade. 

This re-installation of the b2biAPI package reverts some customisation previously applied, back to the defaults shipped with the new product version.

Theoretically there is a customer_override option to set noapp.retain.libertyProps.customization=true

There are some limitations with this option.

1) It causes upgrade failures as outlined in B2Bi 6.2.2.0 documentation (https://www.ibm.com/docs/en/b2b-integrator/6.2.2?topic=integrator-known-issues)

2) It only seems to work for customisation applied in server.xml, and does not seem to retain key.p12 and jvm.options.

For security purposes, customers add their own company keystores to secure the API interface, effectively replacing the default key.p12 file. One idea is to retain the current keystore when upgrading, and ideally should be specified in a separate property rather than requiring the default to be updated. Alternatively have a property to replace or retain the keystore, whichever is easier.

It's also not uncommon to customise jvm.options. Typical changes include increasing memory (Xms/Xmx) often under IBM's direction, and these values are reverted during an upgrade when jvm.options gets replaced. This new change/idea should also preserve jvm.options customisation.