Dockerised btcpp_sample

[cardboardcode]

Purpose Of Pull Request :bookmark:

Hi @facontidavide, thank you for this simple example of using BehaviorTree.CPP. Just started learning to use Behavior Trees in my own projects and your guides have been very helpful.

The PR is to simply add a verified Dockerfile to allow newcomers to easily set up and run btcpp_sample.

Steps To Reproduce :books:

1. Download the repository:

git clone https://github.com/cardboardcode/btcpp_sample.git --depth 1 --single-branch --branch feature/dockerise && cd btcpp_sample

2. Build the docker image:

docker build -t btcpp_sample:latest .

3. Run btcpp_sample in a docker container:

docker run -it --rm \
	--name btcpp_sample_c \
btcpp_sample:latest bash -c "./btcpp_sample"

Verify ✔️

You should see the following output to know that it worked:

this works too
The answer is 42