initial refactory

Refactoring corsika/core corsica/framework/geometry

...

refactory: corsika/framework/sequence

refactorying...

header.h -> header.hpp + other refacorying...

...

refactory media directory...

refactory: corsika/processes

...

refactoring...

testing...

Sibyll headers...

Pythia headers...

module sub-dir

some floating cc files around

eliminate relative include paths on top directories

fixing include file paths, remove quotes from include directives, fix remaining include guards and correct file names ...

unit tests: fixing include file paths, remove quotes from include directives, fix remaining include guards and correct file names ...

corsika/detail inclusion

corsika/detail changes

corsika::secondary_namespaces supressed in favor of detail

more include guards, relative file path, etc ...

nested class promotion to corsika::detail

Inteface to Pythia

one more relative path...

eliminating files...

dependencies managment...

...

dependencies refactory

adding corsika/modules and catch2

build scripts for UrQMD

make modules compile

cmake

first working vesion of new fwk

need to generate some header files

build scripts for dependencies

sibyll works now

proper file endings in many places

On recent versions of Fedora and CentOS, the pythia8-devel packages
provided by the OS do not provide `pythia8-config` which causes the
current FindPythia method to fail. If `pythia8-config` is not found,
FindPythia now attempts to manually find Pythia8 in the standard
install directories.