Avoid warning "no explicit project encoding"

Avoid warning "no explicit project encoding"

Eclipse 2022-06 raises that warning for each project without explicit
encoding. We can avoid the warning by adding explicit project settings
for the otherwise implicit encoding.

There is no functional change, neither for users of Eclipse nor for
users of other IDEs or build tools.

Signed-off-by: Michael Keppler <Michael.Keppler@gmx.de>
Change-Id: I30a6f1369ef09bd445f5730628d01772db2ee7b3