[refactory-2020] Updating PRNG dependent code. Singleton class updated to enable building and running tests

rename framweork/sequence int framework/process

remove all dynamic build files from main corsika directory, move into src

re-added main/shower

fixed wrong file locations

Update corsika.hpp. Re-defining the version macros.

Update corsika.hpp

Update CONTRIBUTING.md

Update MAINTAINERS.md
Deleted FIXME.md

Deleted AUTHORS

Update COLLABORATION_AGREEMENT.md

Update .clang-format

Update .gitlab-ci.yml

added packages: proposal, conex, cnpy, spdlog, lcov, corsika-data

prevent in-source builds

fotran language

flags, sections

build types

fixed stack_example

rename directories

corsika8 interface target

fixed few compilation, dependency issues in new system

clang error

simpler cmake files, using functions, re-introduce run_examples target

clang format

copyright notices

fixed CI script, clang-format

simplify ctest output

better interfaces for urqmd and qgsjII, conex

updated conex, data cmake integration

build system cmake updates

also updated corsika.hpp

added earth radius

moved static_pow from corsika::units::si::detail to corsika::units

updated units::si namespaces throughout the project

No python jobs

removed a lot of stray using namespaces and corsika::units::si in entire codebase

[refactory-2020] stack implementations: updated

[refactory-2020] stack implementations: updated

[refactory-2020] stack implementations

[refactory-2020] stack implementations: !290 headers

[refactory-2020] stack implementations: !290 headers