Change FBAE directories to follow a Maven package like structure

[simatic]

Current FBAE directory structure is not consistent enough. We propose to have:

• doc
• res
• src
  • core // Contains current lib directory
  • main // Contains current main directory
  • test // Contains current tests directory
• utils

Moreover

• All files directly at the top level of src/core will contain namespace fbae { namespace core {
• All files in a subdirectory of src/core will contain namespace fbae { namespace core { and as many namespaces as directory level. For instance, AlgoLayer/Sequencer/Sequencer.h and AlgoLayer/Sequencer/SequencerMsg.h will be in namespace fbae { namespace core { namespace AlgoLayer { namespace Sequencer
• All files directly at the top level of src/test will contain namespace fbae { namespace test {
• All files in a subdirectory of src/test will contain namespace fbae { namespace test { and as many namespaces as directory level. This implies that current tests will be moved to dedicated directories. For instance, tests/AlgoLayer/AlgoLayer/SequencerTest.cpp will be moved to tests/AlgoLayer/AlgoLayer/Sequencer/SequencerTest.cpp and its namespace will be; namespace fbae { namespace test { namespace AlgoLayer { namespace Sequencer