44411 use Mars M3

- use latest available eclipse platform milestone 
in preparartion for Tycho 0.22.0
- fix for incompatible Jetty chnage contributed by
Pascal Rapicault

Bug: 44411
Change-Id: I09894313948dcf754d81fc36c2c21094f4719569
Signed-off-by: Jan Sievers <jan.sievers@sap.com>
Also-by: Pascal Rapicault <pascal@rapicorp.com>