Add section to add InstantOn checkpoint layer to the application container image.

[tjwatson]

Once InstantOn support for Spring Boot 3 is released we should update this guide for an optional step to add an InstantOn checkpoint layer to the application container image.

[gkwan-ibm]

hi @tjwatson does instantOn support Spring Boot 3 now? If not, would you tell post the feature #, so that we can monitor it?

[gkwan-ibm]

hi @yeekangc and @lauracowen

What do you think to add a subsection before the Tearing down the Docker container? It will be an optional step if users are using a Linux box with certain requirements., e.g. kernel version.

[tjwatson]

hi @tjwatson does instantOn support Spring Boot 3 now? If not, would you tell post the feature #, so that we can monitor it?

Epic OpenLiberty/open-liberty#25594 which has target:24006