upgrade to spring-boot 3 (cleaned)

[planetf1]

Description

• Update to Spring 6/Springboot 3 as per @bogdan-sava 's work in Upgrade to spring-boot 3 / java 17 #7416

This PR is a rebuilt version of the above which cleans up the commit history and addresses some merge conflicts

Methodology

• current branch off main
• cherry picked all original authored commits
• 3 way merge in intellij (most conflicts were around dependency versions) -
• ran full gradle build with FVT
• run maven build (-Pquick -DskipFVT) cleanly

Notes

• maven build has a few (easily fixed) issues with checkstyle & errorprone. However the runtime tests do fail with a log4j conflict. My understanding @lpalashevski is that you are not using maven once the spring6 change goes in, so this is of no concern. I can look further if required.
• I've not done testing of ui chassis etc - only the automated UT in the build, and of course our FVTs
• I noticed some further gradle changes needed to update dependencies, address some excluded checks. However for clarity I think it's best to stick with the levels here for an initial checkin as it's in the spirit of the original changes, and then I will later raise a PR for these updates - most of which are unrelated.

Related Issue(s)

Fixes #7225

Testing

• Standard built UTs, (including ui-chassis launch test) and FVTs
• Charts will be tested prior to release

Release Notes & Documentation

Additional notes

[planetf1]

@bogdan-sava @lpalashevski I would like to propose we include this fix soon.

I'm about to do some gradle refactoring to fix our BOMs which is going to be messy. I am happy to manage the merge, but even better if we can get this fix in ASAP as it gives time for everyone to use the updated spring levels, to apply any additional dependencies, and be confident before we branch next week.

For this modified PR I needed to do a 3 way merge. I opted to do this in intelliJ as I wanted to carefully check each change wrt dependencies in particular.

I have suggested a simpler approach for another PR where we had an extended history - see odpi/egeria-charts#237 so happy if you prefer to take that route instead.

[lpalashevski]

I agree to proceed with this PR and get it to main asap.
I did quick regression check locally both ui and server chassis are starting up and working fine so this is good base for the spring major migration.
@bogdan-sava agree?