Make IniSettingsProvider a singleton in order to make sure IniFileChain is shared (again, regressed in a previous commit), and fixed many tests. Changed CacheTest from integration to unit.

The link was displayed over the top menu on small screens.

#7580 Piwik now includes certificates so that updating over HTTPS works even if the local PHP install doesn't have root certificates installed

This new file is included by `Piwik\Http::configCurlCertificate()`

Conflicts:
	tests/UI/expected-ui-screenshots

Fixing some integration tests, make sure IniFileChain is correctly shared among Piwik kernel globals.

Fixing unit tests, includes environment creation/destruction to UnitTestCase base class + ability to override environment in UnitTestCase.

[automatic translation update] Updated 71 strings in 22 languages (bg, nb, nl, fi, cs, da, de, el, es, et, fa, fr, it, ja, pl, ro, ru, sl, sr, sv, tl, tr)

Create PluginList & GlobalSettingsProvider interfaces for hard-coded Piwik kernel components. These objects are used to create the DI container and thus cannot be overidden through DI. Currently only used in DI, though both interfaces should be used by Plugin\Manager + Config.

The container now uses IniFileChain, which means it doesn't need the Config object anymore.

Remove uses of Config::init(), Config::clear() and Config::setTestEnvironment(). Replace last w/ mock config class, which is closer to use of DI.

Adding logging statements to SegmentArchivingRequestUrlProvider to help w/ future debugging.