* enh(doc): change doc layout
* enh(project): add license file

* test(perl): tests fixed to match last changes in clib.
* cleanup(cmake): cleanup of CMakeLists.txt

REFS: MON-6508

* enh(logger): add a common folder, for common sources.

* enh(perl): cleanup perl connector code.

* enh(ssh): cleanup code.

* enh(ssh): switch to spdlog.

* fix(chore): fix compile on centos7

* enh(perl): switch to gtest

* fix(perl): remove some dead code.

* enh(tests): switch to googletest.

* enh(log): add spdlog support for perl_connectors.

* fix(chore): use same connectors version for both connectos.

* fix(perl): fix compile

* cleanup(perl/checks): headers coding style

* cleanup(perl/orders): headers coding style

* cleanup(perl): headers coding style updated

* cleanup(perl/checks): c++ files coding style updated

* cleanup(perl/orders): c++ files coding style updated

* cleanup(perl): c++ files coding style updated

* fix(ssh): Failing tests compilation enabled.

* cleanup(ssh/checks): headers coding style updaed

* cleanup(ssh/orders): headers coding style updated

* cleanup(ssh/sessions): headers coding style updated

* cleanup(ssh): headers coding style updated

* cleanup(ssh/checks): c++ files coding style updated

* cleanup(ssh): c++ files coding style updated

* cleanup(ssh/orders): c++ files coding style updated

* cleanup(ssh/sessions): c++ files coding style updated

* cleanup(ssh/test/checks): c++ files coding style updated

* cleanup(tasks): classes inherited from tasks are updated to match clib

* cleanup(pipe_handle/buffer_handle): classes updated due to changes in clib::handle.

* fix(various): multiplexer is restored and listeners are cleanup

* cleanup(various): Many little changes

* fix(session): Deadlock fixed.

* cleanup(reporter): Not needed code removed.

* cleanup(orders/parser): unused code removed.

* cleanup(ssh/session): unused functions removed

* cleanup(parser/reporter): unused functions removed - changes due to handle_listener changes

* cleanup(gitignore): little update

* fix(perl): clib singletons api is changed.

* fix(ssh): clib singletons api changed

* fix(ssh/test/timeout): clib singletons api changed

* cleanup(ssh/test/orders): c++ files coding style updated

* fix(ssh/test/reporter): clib singletons api changed

* cleanup(ssh/test/credentials): c++ files coding style updated

* cleanup(benchmark): coding style updated

* fix(perl/options): unused code removed.

* enh(ssh): auto_ptr replaced by unique_ptr

* enh(ssh): concurrency::mutex replaced by std::mutex

* enh(connector): WIP to suppress concurrency objects from clib

The goal here is to use standard ones.

* enh(concurrency): Standard library used for threads stuff

* fix(test): Failing tests disabled

* cleanup(ssh): debug functions removed.

feat(perl,ssh): add --log-file option to connectors.

WEB-709 #to-test Discard session on I/O error.

This fixes #5797.

Centreon Connector Perl works parsing Perl scripts in a main
process. When a script execution is requested, the Connector
fork()s itself and child processes run one of the already parsed
script. However because of the fork() mechanism, children inherit
file descriptors of pipes already open towards previously forked
children. This behavior can freeze Centreon Connector Perl
(read/write on the other end of pipe maintained alive by a dead
process). This commit closes all unnecessary file descriptors in
children.