NIFI-10897 Replace Spring Security Base64 with java.util.Base64

[exceptionfactory]

Summary

NIFI-10897 Replaces usage of the deprecated Spring Security Base64 class with the standard java.util.Base64 decoder. Additional changes include replacing deprecated usage of FormatUtils.getTimeDuration() with FormatUtils.getPreciseTimeDuration().

Tracking

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Issue Tracking

• Apache NiFi Jira issue created

Pull Request Tracking

• Pull Request title starts with Apache NiFi Jira issue number, such as NIFI-00000
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Build

• Build completed using mvn clean install -P contrib-check
  • JDK 8
  • JDK 11
  • JDK 17

Licensing

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Documentation

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[MikeThomsen]

Will merge once the build finishes.