Expose utis/fs/file.hpp and temp.hpp on API

[kontura]

It can be used in copr_plugin/json.cpp and I would like to use it in history store command.

Made as a part of: #999

[j-mracek]

I have nothing against making the code public, but I would prefer to revisit exceptions and logging when something fails.

It throw std::filesystem::filesystem_error(), and the question is whether it should inherit from libdnf exceptions to prevent core dumps.

[kontura]

I have nothing against making the code public, but I would prefer to revisit exceptions and logging when something fails.

It throw std::filesystem::filesystem_error(), and the question is whether it should inherit from libdnf exceptions to prevent core dumps.

That sounds like a good idea to me, I will do the changes.

[kontura]

@j-mracek I have added a commit with the new exception.

[kontura]

Test update: rpm-software-management/ci-dnf-stack#1413 - It is needed because the text of the exception changed a little.

[j-mracek]

LGTM