Configurable branding

For every component, make sure the default branding and logo are using the OpenConext brand.

@oharsta : Some organisations will use other words for units, roles and others, and thus need other strings in the translation. Change /client/src/locale/I18n.js to :

Implementation hint:

• Look for en-override.js and/or nl-override.js in the same directory
• If the file(s) exist, use the translations from the -override file
• The -override file will have the same format as the main translation file, but will not have all the elements

Let's assume Portugal is getting involved. Identify all SURF logo's and make this configurable. Configuration for available languages.

@phavekes will create override files and logo's for the SURF build of this Openconext project. That can be used as an example for other organisations that need customization.