Dashboard: Add photo credits and background picture requirements to Readme

[jancborchardt]

Just so we have the links, modification notices, and requirements also in one place. :)

[faily-bot]

🤖 beep boop beep 🤖

Here are the logs for the failed build:

Status of 33007: failure

acceptance-app-files-sharing-link

• tests/acceptance/features/app-files-sharing-link.feature:101

Show full log

  Scenario: owner sees folder created in the public page of an editable shared folder # /drone/src/tests/acceptance/features/app-files-sharing-link.feature:101
    Given I act as John                                                               # ActorContext::iActAs()
    And I am logged in                                                                # LoginPageContext::iAmLoggedIn()
    And I create a new folder named "Editable shared folder"                          # FileListContext::iCreateANewFolderNamed()
    And I close the details view                                                      # FilesAppContext::iCloseTheDetailsView()
    And I see that the details view is closed                                         # FilesAppContext::iSeeThatTheDetailsViewIsClosed()
    And I share the link for "Editable shared folder"                                 # FilesAppSharingContext::iShareTheLinkFor()
    And I set the shared link as editable                                             # FilesAppSharingContext::iSetTheSharedLinkAsEditable()
    And I write down the shared link                                                  # FilesAppSharingContext::iWriteDownTheSharedLink()
      Element is no longer attached to the DOM
      For documentation on this error, please visit: http://seleniumhq.org/exceptions/stale_element_reference.html
      Build info: version: '2.53.1', revision: 'a36b8b1', time: '2016-06-30 17:37:03'
      System info: host: '7abe1f233931', ip: '172.18.0.2', os.name: 'Linux', os.arch: 'amd64', os.version: '4.15.0-76-generic', java.version: '1.8.0_91'
      Driver info: driver.version: unknown (WebDriver\Exception\StaleElementReference)
    And I act as Jane                                                                 # ActorContext::iActAs()
    And I visit the shared link I wrote down                                          # PublicShareContext::iVisitTheSharedLinkIWroteDown()
    And I see that the current page is the shared link I wrote down                   # PublicShareContext::iSeeThatTheCurrentPageIsTheSharedLinkIWroteDown()
    And I create a new folder named "Subfolder"                                       # FileListContext::iCreateANewFolderNamed()
    And I see that the file list contains a file named "Subfolder"                    # FileListContext::iSeeThatTheFileListContainsAFileNamed()
    When I act as John                                                                # ActorContext::iActAs()
    And I enter in the folder named "Editable shared folder"                          # FileListContext::iEnterInTheFolderNamed()
    Then I see that the file list contains a file named "Subfolder"                   # FileListContext::iSeeThatTheFileListContainsAFileNamed()