Support hard links for similar images and videos with -L

[blob79]

This ignores matches for files that have the same inode.

This only works on Unix.

[qarmin]

Not sure if this will not have big performance impact with bigger folders, because comparing big number of paths are quite time consuming(paths are compared by each component alone)

[qarmin]

Thanks!

[qarmin]

Looks that one test is flaky

failures:

---- common_dir_traversal::tests::test_traversal_group_by_inode stdout ----
thread 'common_dir_traversal::tests::test_traversal_group_by_inode' panicked at czkawka_core/src/common_dir_traversal.rs:769:17:
assertion `left == right` failed
  left: [FileEntry { path: "/tmp/.tmpZCDWnm/a", size: 1, modified_date: 100 }, FileEntry { path: "/tmp/.tmpZCDWnm/c", size: 1, modified_date: 100 }]
 right: [FileEntry { path: "/tmp/.tmpZCDWnm/c", size: 1, modified_date: 100 }, FileEntry { path: "/tmp/.tmpZCDWnm/a", size: 1, modified_date: 100 }]
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace


failures:
    common_dir_traversal::tests::test_traversal_group_by_inode

test result: FAILED. 27 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.08s

error: test failed, to rerun pass `-p czkawka_core --lib`
Error: Process completed with exit code 101.

[blob79]

Should be fix here #1209.