[ci] Fix misleading test (using target_package variable as source_package

[api][webui] "filter" -> "action"

after_filter and skip_filter are deprecated and will be removed in Rails 5.1

Revert "Revert "Revert changes to recover nyan-cat-formatter and use UnicornFormatter""

Revert "Revert changes to recover nyan-cat-formatter and use UnicornFormatter"

[api][webui] "before_filter" -> "before_action"

[vagrant] added option to start multiple workers

DEPRECATION WARNING: before_filter is deprecated and will be removed in Rails 5.1. Use before_action instead.

[api][webui] Remove outcommented inflections.rb initializer

Revert changes to recover nyan-cat-formatter and use UnicornFormatter

[api][webui] ActiveRecord "uniq" -> "distinct"

avoid warnings of usage of uniq will be dropped in rails 5.1

Hopefully catched all AR places and only AR places ....

Added new functionality to really delete removed projects that got moved into projects/_deleted.

--remove-deleted-project <removed project>

The function will also remove all packages/sources not belonging to any other project anymore.

Submission from a read protected project to maintenance. maintenance team
should still be able to see the diff.

[api] Fix issue #2150 - webui project meta editor broken

[ci] project_controller.rb#add_maintained_project

Test for app/controllers/webui/project_controller.rb#add_maintained_project

Pair programming with @Ana06, and @bgeuken

Remove P0 label from CONTRIBUTING.md

With f8ac9e47 some previously dead code,
that enabled no_backend_write, became active and prevented update_to_xml
to write to the backend.

Group debugging with Ana, Eduardo, Henne and Manuel.

[api][webui] Fix deprecated string callback

Remove P0 label from the Contribution readme as it does not exist.

Closes https://github.com/openSUSE/open-build-service/issues/2146

Improve remove_maintained_project test

DEPRECATION WARNING: Passing string to define callback is deprecated and will be removed in Rails 5.1 without replacement.

Improve project_controller#remove_maintained_project test:

- Remove unnecessary comment.
- Check that the maintained project is truly removed in the successful case.

This broke with 878e479f

=======

CodeQualityTest
  test_code_complexity                                            FAIL (11.83s)

Minitest::Assertion:         'RequestController#render_request_collection' => 82.38,

        test/unit/code_quality_test.rb:143:in `block in <class:CodeQualityTest>'
        test/test_helper.rb:124:in `block in __run'
        test/test_helper.rb:124:in `map'
        test/test_helper.rb:124:in `__run'

FATE#320699

If -w <num> is defined <num> workers will be started insted of just one.

Fix bs request counter

[ci] Fix monitor controller spec

Remove unnecessary line in project controller spec

Fix Makefile to support 'make all' command.