Add activation command for micromamba

[hguandl]

Attempt to support #20919.

Currently, vscode-python can partially support micromamba with the following settings:

python.condaPath: "/usr/local/bin/micromamba"
python.locator: "native"

The extension can recognize the environments, however, it fails to activate the environment properly. This PR adds the activation script for micromamba, which is a self-contained executable and does not have the base environment.

Example
Suppose there is an environment named foo. The micromamba executable is located at /usr/local/bin/micromamba.

• Current behavior: source /usr/local/bin/activate foo;
• Expected behavior: micromamba activate foo.

Caveats
It is difficult to check whether the executable is micromamba, as there is no deterministic API available. Currently, the implementation relies solely on checking the executable's name.

Tested on macOS (zsh) and Windows (PowerShell).

[hguandl]

@microsoft-github-policy-service agree

[karthiknadig]

Thanks for the PR. I will take a look.

Just FYI, if you want to provide a fully featured support for micromamba consider using https://github.com/microsoft/vscode-python-environments extension API to build a micromamba extension.