This adds the existing c42f/tinyformat@689695c of tinyformat as a subtree, and extracts the modifications that had been made to a utilstrprintf.h wrapper file which is included instead of tinyformat.h directly.
The benefits being that this should be easier to verifiably update and clearer what changes are being introduced, while making it easier to identify tinyformat.h as a dependency rather than a project file, and apply special treatment relative to that fact.
This re-opens #13842