docs: Include the required jq dependency (#492)

#### Motivation
Followed the quickstart and ran into "jq not found" when running the
following command. [Quickstart
link](https://github.com/kserve/modelmesh-serving/blob/91b610bd1bcd8d5264dcd696db4e2b65730f7468/scripts/self-signed-ca.sh#L136-L139)

```./scripts/install.sh --namespace modelmesh-serving --quickstart --enable-self-signed-ca```


The following change made jq a necessary dependency:

https://github.com/kserve/modelmesh-serving/blob/91b610bd1bcd8d5264dcd696db4e2b65730f7468/scripts/self-signed-ca.sh#L136-L139

#### Modifications

Modified the list under the following link to point to where jq can be downloaded or installed https://github.com/kserve/modelmesh-serving/blob/main/docs/quickstart.md#prerequisites

#### Result
The prerequisites list has the link detailed below.

---------

Signed-off-by: medinad96 <[email protected]>

docs/install/install-script.md

@@ -63,6 +63,8 @@ A list of Kubernetes namespaces `--user-namespaces` is optional to enable user n
 
 The `--quickstart` option can be specified to install and configure supporting datastores in the same namespace (etcd and MinIO) for experimental/development use. If this is not chosen, the namespace provided must have an Etcd secret named `model-serving-etcd` created which provides access to the Etcd cluster. See the [instructions above](#setup-the-etcd-connection-information) on this step.
 
+The `--enable-self-signed-ca` flag below requires [jq](https://jqlang.github.io/jq/download/) to be installed.
+
 ```shell
 kubectl create namespace modelmesh-serving
 ./scripts/install.sh --namespace modelmesh-serving --quickstart --enable-self-signed-ca
@@ -103,7 +105,9 @@ The `--namespace-scope-mode` will deploy `ServingRuntime`s confined to the same
 
 You can optionally provide a custom ModelMesh Serving image with `--modelmesh-serving-image`. If not specified, it will pull the latest image.
 
-The ModelMesh controller uses a webhook that requires a certificate. We suggest using [cert-manager](https://github.com/cert-manager/cert-manager) to provision the certificates for the webhook server. Other solutions should also work as long as they put the certificates in the desired location. You can follow [the cert-manager documentation](https://cert-manager.io/docs/installation/) to install it. If you don't want to install `cert-manager`, use the `--enable-self-signed-ca` flag. It will execute a script to create a self-signed CA and patch it to the webhook config.
+The ModelMesh controller uses a webhook that requires a certificate. We suggest using [cert-manager](https://github.com/cert-manager/cert-manager) to provision the certificates for the webhook server. Other solutions should also work as long as they put the certificates in the desired location. You can follow [the cert-manager documentation](https://cert-manager.io/docs/installation/) to install it.
+
+If you don't want to install `cert-manager`, use the `--enable-self-signed-ca` flag. It will execute a script to generate the self-signed CA certificate and then restart the webhook pod to include the certificate in the config. This flag requires [jq](https://jqlang.github.io/jq/download/) to be installed.
 
 - [cert-manager latest version](https://github.com/cert-manager/cert-manager/releases/latest)
 

docs/quickstart.md

@@ -14,6 +14,7 @@ To quickly get started using ModelMesh Serving, here is a brief guide.
 - A Kubernetes cluster v1.23+ with cluster administrative privileges
 - [kubectl](https://kubernetes.io/docs/tasks/tools/#kubectl) and
   [kustomize](https://kubectl.docs.kubernetes.io/installation/kustomize/) (v4.0+)
+- [jq](https://jqlang.github.io/jq/download/)
 - At least 4 vCPU and 8 GB memory. For more details, please see
   [here](install/README.md#deployed-components).