feat: front created, handling routing and basic UI

internal/clientstub/main.js

internal/rootmux/rootmux.go

pkg/oidc2server/oidcserver.go

web/assets/brand/brand.js

web/assets/brand/favicon.ico

web/assets/brand/logo.svg

web/assets/brand/manifest.json

web/assets/spinner.svg

web/components/auth/auth.js

web/components/matcher/matcher.js

web/index.html

web/main.js

web/services/common/common.js

web/services/common/errors.js

web/services/messages/messages.js