Refreshed the copy of "Help" page

Update log-analytics repo (for https://github.com/piwik/piwik-log-analytics/issues/63 & https://github.com/piwik/piwik-log-analytics/issues/62 ).

Refs #7312, fix bug where config file is saved w/ sections in incorrect order. Bug occurs due to incorrect sorting that sorts sections according to which files they appear in, but not where they appear in individual files.

Adding environment validation class to centralize all config.ini.php + related file checking (both in code & in time (so done in one place in code & one time in execution)).

Make Config::reload a protected member so Config is generally setup once and not reloaded w/ different files later.

That happens a lot when switching branches.

Documenting new classes + removing PluginList::getInstalledPlugins method since it is not required for this PR.

refs #5099

Fixing two more system test failures, including one caused by the static cache in Archive.php never being cleared, and the environment not existing in web archiving.

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.