Read config, email and license files UTF-8 encoded, fixes DS-1469 partly

Changes the way the email, license and config files are read. With this
commit these file are expected to be UTF-8 encoded.

DS-1469 has to problems: mvn does not read the build.properties UTF-8 encoded and can scramble some propertie values. DSpace did not read the files mentioned above UTF-8 encoded and scrambled them a second time. This pull request fixes the DSpace part but not the maven part.

This patch should be added to dspace master and the dspace 3.x branch.