Update to MP6.1

[gkwan-ibm]

address issues:

• https://github.com/OpenLiberty/guides-common/issues/1021
• https://github.com/OpenLiberty/guide-microprofile-istio-retry-fallback/issues/122

Review changes

• [x] pom.xml
  • microfile-profile is 6.1, and dependencies
  • LMP 3.10
  • default. should be removed
  • ports 9090,9453,9091,9454 if guide uses local kube
• [x] server.xml
  • feature version
• [x] index.html
  • feature version
• [x] update lgdev with version-update-mp61 branch
• [x] do end-to-end test and review content carefully
  • clone the version-update-mp61 branch
  • if index.html has changes, make sure the links work

[gkwan-ibm]

need https://github.com/OpenLiberty/guides-common/pull/1033