* refs #7983 let plugins add or remove fields to websites and better settings api

* * Hide CorePluginsAdmin API methods
* More documentation
* Added some more tests

* improved updates API for plugins

* better error code as duplicate column cannot really happen when not actually renaming a colum

refs https://github.com/piwik/piwik/commit/4c334be38b8426f54a7e6ab314a82ec25ce49c81#commitcomment-16700320

Add new renameUserSettingsModuleAndAction event handlers to DeprecatedMethodsTest so they will be removed in 3.0.

As the plugin does now nothing anymore, I removed it.

Why? I would simply remove those methods but we might want to release a Piwik 2.13.1 soon and I don't want to remove those methods in a patch version update.

* Store subtables in chunks of 100 subtables per blob. Those 100 subtables are stored
  serialized as an array: array($subtableID => subtableBlob). The first 100 subtables are
  stored in "chunk_0", the next 100 subtables are stored in "chunk_1", ...
* Subtable Ids are now consecutive from 1 to X
* We do no longer serialize the whole Row instance when archiving, instead we only
  serialize the Row's array which contains columns, metadata and datatable. This is not
  only more efficient but allows us to refactor the Row instance in the future (although
  we will always have to be BC)
* Faster row implementation: Columns, Metadata and Subtables access is much faster now

postponing deprecation window as we are planning 2.11.2 and we can't break API in minor version (semver).
they can be broken in 2.12.0 planned for March

The `tmp/` path was hardcoded everywhere, which resulted in using `SettingsPiwik::rewriteTmpPathWithInstanceId()` to rewrite it for specific use cases.

I've moved that path into the config, and replaced all hardcoded usage (and calls to `rewriteTmpPathWithInstanceId()`) by a `get()` from the container.

Getting entries from the container is a bad practice and dependency injection should be preferred, but we do baby steps. When refactoring those classes to DI, we'll replace calls to the container with proper dependency injection.
Another thing we'll need to do too is move the hardcoded *sub-path* of `tmp/` (e.g. `tmp/sessions/`) into the config also (but again: baby steps).

Another future step would be to remove completely instance ID and let it be handled by a plugin (or by end-user config). Having the `tmp/` path in the config means that plugins or users can override it and know it will be taken into account everywhere in Piwik.

refs #5940 moved files into a subfolder framework, added autoloader to remove duplicated code to load autoload.php and to be able to register more autoloaders (eg for test files) on demand. This I got read of many includes that had to be updated all the time and that had to be updated all the time when moving iles

we will deprecate old test classes in 4 months and not in 2, simplified test run by only allowing short version, added some examples

refs #5940 we might stay backwards compatible this way for 2 months. moved some tests from unit to integration and explained when a test is a unit test, an integration test or a system test.

refs #5940 put tests in correct folders, better testsuite names, some tests still fail and I cannot figure out why

refs #6140 easier way to define URLs for menu items and introducing a method to addItem without boolean parameter

Piwik is a free/libre analytics platform. Refs #4455 GNU Package requirement to use free/libre instead of open source

refs #5192 added some doc blocks and prevent the menu hooks from appearing in the documentation as they are deprecated