Opinion of the European Economic and Social Committee on the ‘Reflection Paper on the social dimension of Europe’ (COM(2017) 206), on the ‘Communication from the Commission to the European Parliament, the Council, the European Economic and Social Committee and the Committee of the Regions Establishing a European Pillar of Social Rights’ (COM(2017) 250 final) and on the ‘Proposal for a Interinstitutional Proclamation on the European Pillar of Social Rights’ (COM(2017) 251 final)