license and news

Important changes concerning legal stuff. Must be dealt with before other people can use the package.

reference: https://cran.r-project.org/doc/manuals/r-release/R-exts.html#Licensing

• Receive info from the legal department.
• Create LICENSE file.
• Put license info in README.
• Put license name in DESCRIPTION. If the license is special, include a reference to the file itself. Do this with a "+" instead of "|" because the UFZ licence will probably restrict the open source license in some way. Vertical bars indicate an alternative instead.
• Do not put the UFZ copyright into the license file. Use a copyright file instead and mention it in the DESCRIPTION in the copyright field.
• Update the date in DESCRIPTION.
• Write a NEWS.md file (start with "first public version"). See https://r-pkgs.org/release.html#important-files.