[Java][Jersey2] Fix typo and script, Log enhancements, HTTP signature, deserialization

[sebastien-rosset]

1. Fix typo in the generated Java jersey2 library
2. Add -p argument to mkdir in the sample scripts
3. Add Level.FINE log statement to help troubleshoot deserialization issues.
4. Add Java jersey2 sample based on OAS 3.0 document with HTTP signature scheme. This helps to validate changes to the mustache templates for HTTP signature do not introduce regressions and can be compiled.
5. Add unit test to validate deserialization of 'oneOf' schema.

PR checklist

• Read the contribution guidelines.
• If contributing template-only or documentation-only changes which will change sample output, build the project before.
• Run the shell script(s) under ./bin/ (or Windows batch scripts under.\bin\windows) to update Petstore samples related to your fix. This is important, as CI jobs will verify all generator outputs of your HEAD commit, and these must match the expectations made by your contribution. You only need to run ./bin/{LANG}-petstore.sh, ./bin/openapi3/{LANG}-petstore.sh if updating the code or mustache templates for a language ({LANG}) (e.g. php, ruby, python, etc).
• File the PR against the correct branch: master, 4.3.x, 5.0.x. Default: master.
• Copy the technical committee to review the pull request if your PR is targeting a particular programming language.

[sebastien-rosset]

@wing328

[wing328]

We're consolidating ./samples/openapi into ./samples and only use OAS 3 spec moving forward so I'll move the new samples you added under ./samples