Automatic plugin install

[Akryum]

When running the vue invoke <name> command, vue-cli could automatically install the @vue/cli-plugin-<name> or vue-cli-plugin-<name>, using the user prefered tool (npm or yarn).
If <name> contains @vue/cli-plugin or vue-cli-plugin, use npm install <name> directly.
Then run the real invoke.

Example:

vue create my-app
cd my-app
vue invoke apollo

[yyx990803]

I kinda hope it's possible to explicitly separate the install and invocation steps.

Maybe instead we can have a different command vue add which combines both.

[zephraph]

Yeah. I was noticing tonight when I tried to add the just plugin to a project just by installing it it didn't automatically make the config updates. I just created an example with vue create with the plugin that I wanted and manually moved over the config.

Having a command like vue add to both install and configure the plugin would be nice.