Add devcontainer configuration

[BrianLakstins]

I've added some files that create a development container for Visual Studio Code in Docker with all libraries needed to start the build process.

I also added a file that forces just LF when using Git to request the code from a Windows system.

The compilation does not complete with the current configuration.

1. The creation of version.h fails. Might be because it already exists. This change to CMakeLists.txt fixes it:

# Create a version.h file
configure_file(
        ${CMAKE_CURRENT_SOURCE_DIR}/include/core/version.h.in
        ${CMAKE_CURRENT_BINARY_DIR}/generated/version.h
)
include_directories(${CMAKE_CURRENT_BINARY_DIR}/generated)

2. I get fatal errors referencing a ../external folder that does not exist in /src/core/logger_json.c

#include "../external/cjson/cJSON.h"

Looks like the file is downloaded if cJSON is not found, but I included it in the Devcontainer. I changed the include references to:

#include <cjson/cJSON.h>

I still got errors after that, but it looks like they may be due to included package versions being newer than from your build system.