Format installer heex templates

[leandrocp]

Ref https://github.com/phoenixframework/phoenix/pull/4793#issuecomment-1119687158

Tasks

• [x] Update templates with latest HTMLFormatter rules
• [x] Fix integration tests
• [x] Fix unit tests
• [x] Update and fix CI

Testing locally

CI is gonna fail until a new LiveView version is released with latest fixes on HTMLFormatter, to test locally and make sure I'm testing the way it's supposed to be tested:

1. Install Elixir v1.13.4 or master

2. Download and apply patch to fetch latest LiveView dep https://gist.github.com/leandrocp/6ffaa7482c58c849d9e5813183e04413

wget https://gist.githubusercontent.com/leandrocp/6ffaa7482c58c849d9e5813183e04413/raw/5bf9f6b7bc54db777188ff37dddfa4636058afb3/phoenix_html_fmt_liveview_master.patch

git apply phoenix_html_fmt_liveview_master.patch

3. Run integration tests

cd integration_test && mix deps.update phoenix_live_view && mix test

4. Run unit tests

cd .. &&  mix test

Or run using Earthly

earthly -P --build-arg ELIXIR=1.10.0 --build-arg OTP=21.3.8.24 +test
earthly -P --build-arg ELIXIR=1.13.4 --build-arg OTP=24.3.4 --build-arg ALPINE=3.15.3 --build-arg RUN_INSTALLER_TESTS=1 +test
earthly -P --build-arg ELIXIR=1.13.4 --build-arg OTP=24.3.4 --build-arg ALPINE=3.15.3 +integration-test

/cc @chrismccord