checking all extensions with foreach

* Use Doctrine instead of legacy db connection
* Add types to variables and returns
* Simplify functions
* Remove unused code

* ext_autoload is not needed anymore, as it is loaded via composer.json
* tx_ter_helper->getLatestVersionNumberOfExtension is not in use anymore
* and the tx_ter_extensionmembers.gif icon was not removed in the previous commits

This change re-implements the generation of the XML file for TYPO3 installations
by moving the relevant code from EXT:ter to ter_fe2.

CombinedExtensionRepository -> does the collection of available extensions
ExtensionIndexService -> handles the XML generation and writing to files

This way, all functionality can be separated and exchanged if necessary.

A CLI command "ter:createExtensionIndexXml" is added which
also shows some more useful output, however the logic is still in
the "UpdateCurrentVersionListTask" class in EXT:ter.

The methods:
tx_ter_helper->requestUpdateOfExtensionIndexFile
tx_ter_helper->writeExtensionIndexfile

are removed, and thus, all of this logic is migrated to Doctrine DBAL.

Root composer.json is adapted so the necessary PHP extensions are available
in your IDE.

Due to the direct call of TER helper the pluginObj is not existing anymore.
Without the UIDs there is no possibility to transfer as TER admin.

Thomas Löffler authored Oct 01, 2019 and Tomas Norre Mikkelsen committed Oct 01, 2019

Also:
* Add composer as facet
* Restructure list view
* Restructure detail view
* Add and improve tests

* Casts uploadComment to string before writing in DB

Since we call the SOAP endpoint for certain actions
of an authenticated user on extensions.typo3.org
(like registering ext keys) and we do not know
the password at this point any more,
we now include the session id in the SOAP request,
so that TYPO3 will login this user before the SOAP
endpoint is triggered.

In the endpoint, we can then just check if a user is
already logged in and whether the username given
matches the username of the logged in user.

By having an inverted condition, attackers
could upload arbitrary extensions by only knowing
the username and the extension key.

When knowing a username of a TER admin,
it was also possible to perform TER admin
commands (like deleting extensions) via SOAP