Update documentation about api keys #664

Job	Run time
Forge Node LTS Matrix	1s
Documentation - Error codes check	1m 9s
Lint - Node.js LTS 16	1m 11s
Lint - Node.js LTS 18	1m 41s
Unit Tests (16)	2m 27s
Unit Tests (18)	1m 54s
Build and Run kuzzle	3m 23s
Functional Tests - jest - Node.js v16	4m 22s
Build and Run kuzzle	4m 29s
Functional Tests - jest - Node.js v18	4m 1s
Functional Tests - http - Node.js v16	8m 7s
Functional Tests - http - Node.js v18	8m 12s
Functional Tests - websocket - Node.js v16	7m 43s
Functional Tests - websocket - Node.js v18	8m 39s
Functional Tests - legacy:mqtt - Node.js v16	8m 48s
Functional Tests - legacy:mqtt - Node.js v18	8m 42s
Functional Tests - legacy:http - Node.js v16	8m 4s
Functional Tests - legacy:http - Node.js v18	8m 21s
Functional Tests - legacy:websocket - Node.js v16	8m 56s
Functional Tests - legacy:websocket - Node.js v18	8m 35s
Cluster Monkey Tests (16)	3m 45s
Cluster Monkey Tests (18)	3m 6s
Deployment Workflow / Build and deploy release on NPM.js	0s
Deployment Workflow / Documentation - Deploy	0s
Deployment Workflow / Build and deploy images to Dockerhub	0s
	1h 55m 36s

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