concore.jl: add Docker runtime wrapper

[avinxshKD]

This adds the Week 7 concoredocker.jl runtime.

This is the Docker-path variant of the current Julia runtime. It follows concore.jl closely, with absolute /in and /out paths and thin read/ write aliases matching concoredocker.py.

[avinxshKD]

The failing jobs appear unrelated to this,
@pradeeban pls take a look and let me know any changes needed :P.

[pradeeban]

@avinxshKD yes, that is unrelated. I am merging.

Do you have any clue what is going wrong though with the C++ test?

This is what failing:
0s
Run g++ -std=c++17 -Wall -Wextra -fsyntax-only tests/test_shm_cpp_smoke.cpp
tests/test_shm_cpp_smoke.cpp:4:10: fatal error: concore.hpp: No such file or directory
4 | #include "concore.hpp"
| ^~~~~~~~~~~~~
compilation terminated.
Error: Process completed with exit code 1.

[pradeeban]

Never mind, you have already fixed it in the next PR. I have merged it now. Thanks.
You are quick. haha.