Merge branch 'develop' of https://gitlab.orekit.org/orekit/orekit.git into develop

checkstyle.xml

...n/java/org/orekit/geometry/fov/EllipticalFieldOfView.java

src/main/java/org/orekit/gnss/HatanakaCompressFilter.java

src/main/java/org/orekit/orbits/FieldOrbit.java

...rekit/propagation/numerical/FieldNumericalPropagator.java

...org/orekit/propagation/numerical/NumericalPropagator.java

...main/java/org/orekit/utils/ImmutableTimeStampedCache.java

...test/java/org/orekit/gnss/HatanakaCompressFilterTest.java

...st/resources/rinex/emptyFile_U_20190320000_15M_30S_MO.crx

...st/resources/rinex/truncateC_U_20190320000_15M_30S_MO.crx