fix compatibility with ms-python

[OdinZhang]

Fixes #878 #855 #576 #434
Many python users like to use conda or something else to control the virtual environment. But code runner does not supprot it. When ms-python extension has been installed, it will firstly execute the command and then activate the virtual environment, so it won't work well with python at the first execution.
I just add an option to make users to choose whether to execute the command with official python extension.

[browneye1826]

Having this issue too. Strange. Only started recently. Even though the Conda environment is set in the workspace, code-runner is still trying to execute with a different Python version, resulting in errors (missing modules etc.).

[OdinZhang]

Having this issue too. Strange. Only started recently. Even though the Conda environment is set in the workspace, code-runner is still trying to execute with a different Python version, resulting in errors (missing modules etc.).

Actually, code runner try to excute the command directly after terminal started, if you use default environment it won't be a problem. When you use another environment, the environment will be activated only after the first execution.