[feature] Add user setting for file extension configuration

[jaketig]

We use .js files instead of .ts files for plugins/apis/composables/stores/etc...

This appears to be hardcoded here: https://github.com/nuxtrdev/nuxtr-vscode/blob/main/src/utils/commands.ts#L3

Any chance this could be made configurable?

[zhaolinlau]

Hi @jaketig , I have opened a PR #159