Add Linux automated build and release.

[RICCIARDI-Adrien]

Automatically build and package the nix platform (for Linux x86_64) when a pull request is opened or when a commit is pushed to the master branch. If a commit is pushed to the master branch, the archived binary is also automatically released to a tag called continuous-build.

See https://github.com/RICCIARDI-Adrien/OpenLara/actions/runs/5919948724/job/16050699820 for a non-master branch push (so without release), https://github.com/RICCIARDI-Adrien/OpenLara/actions/runs/5919935315/job/16050673601 for a master branch push followed by the automatic release https://github.com/RICCIARDI-Adrien/OpenLara/releases/tag/continuous-build.

[RICCIARDI-Adrien]

Hi @XProger, if the CI is interesting you, I can try to add other architectures later on. What do you think of this PR ?

[synthic]

Would love to see automated builds for the win platform as well.