This reverts commit a03cb3c9.

- Catching exceptions and reporting them via flash messages in each controller action
- Reporting success via flash messages
- Checking response of typoScriptBackend web resource for errors and handling the errors
- Fixing AccessArrayViewHelper not to throw error if given array is null
- A try to convert Fluid flashMessages html to html which can be styled by Bootstrap

- types in side menu are sorted by categories
- a type can be assigned to a category through it's edit form

- Login form with login controller. Same as on forger package. Both login forms work.
- Configuration required for login in Setting.yaml.
- SGalinski.TypoScriptReference:Admin role defined in Policy.yaml. User must have this role if he wishes to edit the data.

- Added select box for TypoScript group, also adapting controller to filter by TypoScript group
- [BUGFIX] using decoded typo3Versions everywhere before rest backend call (decoded like this: 'all' => NULL, 'current' => 99999)
- Currently the app is little buggy - properties are not well filtered by versions

Filter by typScript group is implemented, but without select box to specify the value, normalGrouup is used as default filter value

This solution has a bug - content of downloaded xml file is doubled.
The content gets doubled after being set to FLOW response...

A type doesn't need to extend a type.

Also extracting a method.

ID is used like identifier

Deletion of property/type is done via PATCH method by setting 'deleted' flag of the property/type
Properties/types, with deleted flag set, are not visible to user.

- If no type is selected, main content is empty
- Deleting panel version of index template
- Using associative array also for the menu
- Using new view variable "selectedTypeId" for making visual selection in the menu

For the menu on the left, only type names and ids are fetched. When a type is clicked, more data is shown about the type in right part of the page. By typeId, additional type data is fetched (including properties).

Important notice: uriPattern: '{@controller}(/{@action})' exists also in Forger package, and that makes conflict. To solve it, SGalinski.TypoScriptReferenceFrontend routes should be included in main Routes.yaml file before forger routes. And it should be prefixed in main Routes.yaml file like this: uriPattern: 'ts/<SGalinski.TypoScriptReferenceFrontend>'