NIFI-9375 Refactor Registry using OSUtils from nifi-bootstrap-utils

[exceptionfactory]

Description of PR

NIFI-9375 Refactors Registry to use OSUtils from nifi-bootstrap-utils to avoid illegal reflective access warnings for Java 11 and remove duplicate code. The change removes the need for a separate OSUtils in nifi-registry-bootstrap.

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[pvillard31]

Merged, thanks @exceptionfactory