package.json: Remove the unneeded Neon/Seshat dependencies.
package.json: Remove the unneeded Neon/Seshat dependencies.

vector-im/riot-web,vector-im/riot-web,vector-im/vector-web,vector-im/riot-web,vector-im/vector-web,vector-im/riot-web,vector-im/vector-web,vector-im/riot-web,vector-im/vector-web,vector-im/riot-web,vector-im/vector-web