- add new method getExtractMethodFromLambdaProposal() to
  QuickAssistProcessor
- add new message to CorrectionMessages
- add new relevance value EXTRACT_LAMBDA_BODY_TO_METHOD to
  IProposalRelevance
- add new tests to AssistQuickFixText1d8

Change-Id: I749fdce7702fa2ff2a656e379534bc518abc0365
Reviewed-on: https://git.eclipse.org/r/c/jdt/eclipse.jdt.ui/+/188802
Tested-by: JDT Bot <jdt-bot@eclipse.org>
Tested-by: Jeff Johnston <jjohnstn@redhat.com>
Reviewed-by: Jeff Johnston <jjohnstn@redhat.com>