Remove most Netlify configuration (#6194)

This removes the in-repository Netlify configuration. There are now two
sites backed by the repository, so we must use the web UI to
control the build settings, as having the configuration in-repository
overrides the web UI settings.

The build settings for the two sites are below, as of this commit. See
the extra step in nomad-ui site’s build step that copies the _redirects
file to the correct destination so things are properly forwarded when
you visit the deployment.

nomad-ui:

base directory: ui
build command: ember build && mkdir -p ui-dist/ui && mv dist/* ui-dist/ui/ && cp ../.netlify/ui-redirects ui-dist/_redirects
publish directory: ui/ui-dist

nomad-website:

base directory: website
build command: bundle exec middleman build
publish directory: website/build

.netlify/state.json

@@ -1,3 +0,0 @@
-{
-  "siteId": "442034dd-3749-45d9-992e-480ab871ee28"
-}

.netlify/ui-redirects

@@ -0,0 +1,2 @@
+/ /ui
+/ui/* /ui/index.html 200

netlify.toml

@@ -1,18 +0,0 @@
-# Netlify is installed under the hc-nomad bot account on GitHub.
-
-[build]
-  # The generated site needs to live at /ui/, so this moves it there after building.
-  command = "ember build && mkdir -p ui-dist/ui && mv dist/* ui-dist/ui/"
-  base = "ui"
-  publish = "ui/ui-dist"
-
-# This ensures that following the link from the PR checks list redirects to the subdirectory.
-[[redirects]]
-  from = "/"
-  to = "/ui/"
-
-# This catches other unknown URLs and lets Ember handle them.
-[[redirects]]
-  from = "/*"
-  to = "/ui/index.html"
-  status = 200