Add simpler development environment

[fcaps]

Currently using the website in docker with a fully started faf-stack is not the simplest thing.
since the website can also run with the services of xyz, this should be the preferred way for new developers.

Tasks:

• can we share "secrets" of the xyz in the repo? @Brutus5000
• updating the readme (maybe even removing the local/fafstack install chapter)
• testing the "ease" of startup from scratch with some devs we can find

[fcaps]

just got the answer, and we can share the xyz .env in the repo.

Tasks:
[] add .env-xyz
[] update README.md to only include the setup with the xyz
[] confirm the steps are working by cloning a fresh copy of the repository

[fcaps]

.env-xyz

# node env is set statically to "development" in the dockerfile, you could override it here.
#NODE_ENV=production

HOST=http://localhost:8020
API_URL=https://api.faforever.xyz
OAUTH_URL=https://hydra.faforever.xyz

# on a local environment with docker, the internal docker-service-domain (faf-ory-hydra:4444) is not reachable for a browser
# you can omit this env and it will fallback to OAUTH_URL if you know what you are doing.
#OAUTH_PUBLIC_URL=http://localhost:4444

# unsing the "production" wordpress because the faf-local-stack is just an empty instance without any news etc.
WP_URL=https://direct.faforever.com
OAUTH_M2M_CLIENT_ID=faf-website-public
OAUTH_M2M_CLIENT_SECRET=banana
OAUTH_CLIENT_ID=faf-website
OAUTH_CLIENT_SECRET=banana
SESSION_SECRET_KEY=bananaa
RECAPTCHA_SITE_KEY=6LeIxAcTAAAAAJcZVRqyHh71UMIEGNQ_MXjiZKhI
# JAVA-API token lifetime in seconds
TOKEN_LIFESPAN=43200
CLAN_INVITES_LIFESPAN_DAYS=30
# Interval for the extractor.js in minutes
EXTRACTOR_INTERVAL=5
# Interval for the getRecentUsers.js in seconds
PLAYER_COUNT_INTERVAL=15