[Clang-Tidy] Encourage the use of emplace

[Skylion007]

Motivation and Context

• Another code modernization clang-tidy rule. This one did find a few performance issues where emplace should have been used (mainly with std::pair and the voxel code.) I am fine with not enabling it by default, but we should at least merge in the code changes if there are no objections. I am also fine downgrading it to a warning. https://clang.llvm.org/extra/clang-tidy/checks/modernize-use-emplace.html

How Has This Been Tested

• Locally

Types of changes

• Docs change / refactoring / dependency upgrade
• Bug fix (non-breaking change which fixes an issue)

Checklist

• My code follows the code style of this project.
• I have read the CONTRIBUTING document.
• I have completed my CLA (see CONTRIBUTING)
• I have added tests to cover my changes.
• All new and existing tests passed.

[mosra]

This looks like a good thing to do for me :)