feat: add Docker build (#41187)

* feat(docker): build and use client and api images

* feat: always use .env

dotenv fails without throwing if the .env file is missing and never
overwrites variables if they already exist. As such, we can use it in
build pipelines.

* fix: remove quotes from env vars

dotenv normalises quoted and unquoted strings (X=x, X='x' and
X="x") all become the same .env object {X: 'x'}. However, Docker's
env_file does not (the three cases are distinct).  As a result, we
should use unquoted strings for consistency.

* fix: provide custom warning when .env is missing

* feat(docker): include client-config

* fix(docker): remove build packages from api image

* fix(docker): run script from correct dir

* fix(docker): correct permissions and dests

* fix(docker): consolidate run steps

This is standard practice, but did not have a noticable affect on the
image size

* fix(docker): clean the npm cache

Prior to this step the image was 1.11GB uncompressed and we got a modest
saving, 1.09GB after.

* refactor(docker): regexless COPY directives

* feat(docker): use alpine

This shrinks the image down to 259MB

* fix(docker): update build scripts

* fix: correct the server Dockerfile RUNs

* DEBUG: expose mysql port for seeding

* chore: update client Dockerfile's node versions

* fix: remove executable permissions from index.js

It's not a cli, so I don't think it needs to be executable.

* chore: update node and remove stale comments

* feat: use ENTRYPOINT + CMD to allow runtime config

* fix: add CURRICULUM_LOCALE arg

* feat: allow client port configuration

* feat: allow api port to be configured

* refactor: use unique variable names for ports

* fix: add default CLIENT_PORT

* refactor: clean up

sample.env

@@ -3,11 +3,11 @@
 # ---------------------
 
 # Database
-MONGOHQ_URL='mongodb://localhost:27017/freecodecamp'
+MONGOHQ_URL=mongodb://localhost:27017/freecodecamp
 
 # Logging
 SENTRY_DSN=dsn_from_sentry_dashboard
-SENTRY_ENVIRONMENT='staging'
+SENTRY_ENVIRONMENT=staging
 
 # Auth0 - OAuth 2.0 Credentials
 AUTH0_CLIENT_ID=client_id_from_auth0_dashboard
@@ -39,17 +39,15 @@ STRIPE_SECRET_KEY=sk_from_stripe_dashboard
 # PayPal
 PAYPAL_CLIENT_ID=id_from_paypal_dashboard
 PAYPAL_SECRET=secret_from_paypal_dashboard
-PAYPAL_VERIFY_WEBHOOK_URL='https://api.sandbox.paypal.com/v1/notifications/verify-webhook-signature'
-PAYPAL_API_TOKEN_URL='https://api.sandbox.paypal.com/v1/oauth2/token'
+PAYPAL_VERIFY_WEBHOOK_URL=https://api.sandbox.paypal.com/v1/notifications/verify-webhook-signature
+PAYPAL_API_TOKEN_URL=https://api.sandbox.paypal.com/v1/oauth2/token
 PAYPAL_WEBHOOK_ID=webhook_id_from_paypal_dashboard
 
 # ---------------------
 # Build variants
 # ---------------------
-
-PIPELINE_ENV=false
-DEPLOYMENT_ENV='staging'
-FREECODECAMP_NODE_ENV='development'
+DEPLOYMENT_ENV=staging
+FREECODECAMP_NODE_ENV=development
 
 # Languages to build
 CLIENT_LOCALE=english
@@ -59,11 +57,11 @@ CURRICULUM_LOCALE=english
 SHOW_UPCOMING_CHANGES=false
 
 # Application paths
-HOME_LOCATION='http://localhost:8000'
-API_LOCATION='http://localhost:3000'
-FORUM_LOCATION='https://forum.freecodecamp.org'
-NEWS_LOCATION='https://www.freecodecamp.org/news'
-RADIO_LOCATION='https://coderadio.freecodecamp.org'
+HOME_LOCATION=http://localhost:8000
+API_LOCATION=http://localhost:3000
+FORUM_LOCATION=https://forum.freecodecamp.org
+NEWS_LOCATION=https://www.freecodecamp.org/news
+RADIO_LOCATION=https://coderadio.freecodecamp.org
 
 # ---------------------
 # Debugging Mode Keys
@@ -74,4 +72,4 @@ DEBUG=true
 LOCAL_MOCK_AUTH=true
 
 # Webhook proxy url from smee.io for PayPal
-WEBHOOK_PROXY_URL=''
+WEBHOOK_PROXY_URL=