Code restructuration

[ProSurfer73]

• Let's merge MacroDatabase and MacroContainer into one single class MacroContainer
• Let's the library from C++17 standard library to check if directory exists and list files inside folders
• Let's create a class MacroLoader from MacroContainer, that will offer method to load this container from a file or a folder.
• let's rename filesystem.cpp/.hpp into macrosearch.cpp/.hpp, as it will only contain function related to the search of macros inside folders.

[ProSurfer73]