message: better Install documentation
diff: mutation {
  - #
  - addSshKey(input: {name: "my-ssh-key", keyValue: "...", keyType: "ssh-rsa"}) {
  - id
  - }
  - addCustomer(input: {name: "customer-name", private_key: "...", sshKeys: ["my-ssh-key"]}) {
  - id
  + # The customer of the project. Can be used for an actual customer (if you use Lagoon in a multi-customer setup),
  + # or just to group multiple projects together. `customer` will hold the SSH Private Key that Lagoon will use to clone
  + # the Git repository of the project (the private key needs to be in a single string, where new lines are replaced by `\n`
  + # see an example in /local-dev/api-data/api-data.sql)
  + addCustomer(input: {name: "customer-name", private_key: "[fill me]"}) {
  + name
  }
  - addOpenshift(input: {name: "my-openshift", console_url:"...", token: "..."}) {
  - id
  +
  + # The OpenShift Cluster that Lagoon should use to deploy to. Yes Lagoon is not only capable to deploy into the OpenShift that
  + # it is running itself, but actually to any OpenShift anywhere in the world. We need to know the following infos for this to work:
  + # `name` - Unique identifier of the OpenShift
  + # `console_url` - URL of the OpenShift console (without any `/console` suffix)
  + # `token` - the token of the `lagoon` Service Account creted in this OpenShift (this is the same token that we also used during installation of Lagoon)
  + addOpenshift(input: {name: "my-openshift", console_url:"[fill me]", token: "[fill me]"}) {
  + name
  }
  - addProject(input:{name: "first-project", customer:"customer-name", openshift: "my-openshift", git_url: "..."}) {
  - id
  +
  + # This is your git repository that should be deployed, it needs to contain a `.lagoon.yml` file so Lagoon knows what it should do.
  + addProject(input:{name: "first-project", customer:"customer-name", openshift: "my-openshift", git_url: "[fill me]"}) {
  name
  customer {
  name
  - sshKeys {
  - id
  - name
  - }
  }
  openshift {
  name
  