Swap erb_template implementation for actual .html.erb file implemenation on Getting started and intro docs.

[master-of-null]

Hi!

I'm part of the Ruby on Rails Link slack community, which is pretty active. We were having a discussion on the benefits of using ViewComponents. And I, having been away from rails for quite a few years and just came back, chimed in saying I was really reluctant to write all my html/erb in a string in the class.

I had briefly looked at the docs a few times, not much in depth, but was just voicing my opinion to find out how others dealt with it. Many of those engaged in the conversation mentioned they weren't a fan that it was the opening demo for ViewComponents and that they rarely ever write using the erb_template method. They told me how they actually use ViewComponents in the wild, and now I'm excited to dig in.

Obviously I could have dug deeper, to find out there are other implementation methods than that ERB string, but still it was the reason I was turned off. Just thought it was worth mentioning!

[joelhawksley]

@master-of-null that's helpful feedback ❤️ . I'd accept a PR that adds the separate file implementation to the opening demo, perhaps with the erb_template method mentioned as an alternative option, as I know it tends to appeal to React folks 😄