Update Import-Package version start ranges

[joakime]

For this and the other range issues you've raised we need to address this in another PR, not this one. If you're happy with the changes to enable jetty-slf4j-impl to work in osgi, please give this issue the thumbs up and open new issue to bump up osgi servlet/jsp api versions.

Originally posted by @janbartel in #4684

[janbartel]

Raised PR #4963

I've removed the explicit numbering for the frequently updated imports and used variable expansion instead: it should make jetty-10 and 11 easier to handle too.