Add `sendDefaultPii` flag to `SentryOptions`.

[maciejwalkowiak]

:loudspeaker: Type of change

• [ ] Bugfix
• [ ] New feature
• [x] Enhancement
• [ ] Refactoring

:scroll: Description

Add sendDefaultPii flag to SentryOptions. Filters out user information and sensitive request headers in Spring Boot integration if this flag is set to false.

:bulb: Motivation and Context

Discussion initially started when working on Spring Boot integration - we want to give users option to decide if detailed user information is sent or not - similar to how it's done in Python integration: https://docs.sentry.io/error-reporting/configuration/?platform=python

Supersedes #527.

:pencil: Checklist

• [x] I reviewed submitted code
• [x] I added tests to verify changes
• [x] All tests passing
• [ ] No breaking changes