Module improvements

[pi0]

Thanks for this module! I'm adding few improvement ideas:

• Array convention for passing module options, is being deprecated. It would be nice supporting top level fathom key in nuxt.config (example)
• It would be nice supporting runtimeConfig for setting analytics id (this way id can be set after build based on deployment). For this, we need to export a function from template file
• Module is better to be installed as devDependency and added in buildModules instead of modules since we don't add any runtime extension by module
• It would be nice adding option types (example)

[tillsanders]

@pi0 Great suggestions, I created a PR to address these! I'm not 100 % sure about the runtime config, though. It works, but there might be a more elegant way? I was expecting this to contain the Nuxt Context, so I could access $config. Instead I had to access publicRuntimeConfig. See here: https://github.com/yabhq/nuxt-fathom/pull/4/files#diff-cdd77182e73349d6c83fbbce1cccf6f15972fbece4dbd9c52eececf1ca3bfcd5R21