Move from poco::file to std::filesystem - Kernel

[peterfpeterson]

This is the first of probably many PRs to move from Poco::File and Poco::Path to std::filesystem. This does not remove all use of Poco::File from Kernel.

Refs #37868

To test:

This is a refactor for modernization. If the existing tests pass, it works.

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[dmitry-ganyushin]

The dependence from the Poco library could be completely eliminated in this PR.

[dmitry-ganyushin]

Looks good!

[dmitry-ganyushin]

Looks good!