Partially move NumberFormatter to DI, refactor NumberFormatterTest so not as many deprecated classes/methods are used, and add tests for NumberFormatter::format().

In NumberFormatter::format() check for percent if value is a string only, since only strings will have a % (avoids floating point issues). Also, forward arguments to formatPercent in NumberFormat::format() and remove percent check in Twig |number filter since it is redundant (NumberFormatter does the same thing).

https://github.com/piwik/piwik/pull/8857