IDE: Support Codespaces

[AlexanderLanin]

As described in the linked issue, this switches py_binary and py_library to aspect_rules_py. This way there is no dependency to the system python executable.

closes #178

[AlexanderLanin]

Bug: bazel run //:format.fix still relies on system python.

vscode ➜ /workspaces/score (codespaces) $ bazel run //:format.fix
INFO: Analyzed target //:format.fix (1 packages loaded, 2017 targets configured).
INFO: Found 1 target...
Target //tools/format:format.fix up-to-date:
bazel-bin/tools/format/format.fix.bash
INFO: Elapsed time: 0.417s, Critical Path: 0.01s
INFO: 1 process: 1 internal.
INFO: Build completed successfully, 1 total action
INFO: Running command line: bazel-bin/tools/format/format.fix.bash
/usr/bin/env: ‘python3’: No such file or directory

[MaximilianSoerenPollak]

Makes sense to have no setup/installation needed for anything, that seems to be the reason to use bazel.

LGTM 👍

[AlexanderLanin]

Yeah they are basically competing technologies. But here I'm using the devcontainer just for installing bazel and bazel does the rest.