Deprecate uberJar mojo parameter and log a warning when used

[famod]

Relates to #14878.

Notes:

• I replaced the remaining usages with Maven properties, not with application properties, because I prefer to keep build related stuff out of application.properties/.yaml, but I have no hard feelings if you want it the other way.
• I stole the pattern for the warning from here: Log warning about the use of NativeImageMojo #14634

[famod]

Not entirely sure about backporting but since #14634 was also backported (to 1.11.1), I think the earlier users are warned the better.