[TASK] Made changes in README.md file for Lelesys.Plugin.ContactForm
[TASK] Added open source license for class files.

Change-Id: Ib411945ac2f08746ef30c3600c5f14cbf1148259
Merge "[TASK] Added open source license for class files."
[TASK] Updated documentation for class files.
[TASK] Fixed issues after upgrade in Neos
[TASK] Changed plugin icon

Change-Id: I1dc08d0f706c0cce862fa66e8bed651fec59a173
[TASK] Added icon for backend module