Update N1C getting started guide with instructions on how to enable metrics collection for a NGINX Plus API with SSL enabled

[dhurley]

Proposed changes

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[github-actions]

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[craigell]

Think we can take out the commented section for http basic auth. Keep the example clear for ssl only.

[nginx-seanmoloney]

Suggested change

	NGINX Agent configuration needs to be update with the following to enable the NGINX Agent to be able to call the NGINX Plus API.
	```
	data_plane_config:
	nginx:
	api_tls:
	ca: "/etc/nginx/certs/nginx-selfsigned.crt"
	```
	#### Configure NGINX Agent to call the NGINX Plus API
	To enable the Agent to call the NGINX Plus API, follow the steps below:
	1. `sudo vim /etc/nginx-agent/nginx-agent.conf`
	2. Open the file for editing
	3. Add the following configuration:

data_plane_config:
nginx:
api_tls:
ca: "/etc/nginx/certs/nginx-selfsigned.crt"

4. Save and Restart
`sudo systemctl restart nginx-agent`

5. Run the following `sudo journalctl -u nginx-agent | grep "NGINX Plus API"`
The following output should be shown: `NGINX Plus API found, NGINX Plus receiver enabled to scrape metrics`

[mjang]

I've made some basic suggestions. IMO, this also should be approved by @shaynesf5 , whose been working on observability for N1 Console.

[mjang]

Suggested change

	Make sure that the `server` and `location` blocks are in the same single configuration file, and not split across multiple files using `include` directives.
	Make sure that the `server` and `location` blocks are in the same configuration file, and not split across multiple files using `include` directives.

[mjang]

Suggested change

	Make sure that the `server` and `location` blocks are in the same single configuration file, and not split across multiple files using `include` directives.
	Make sure that the `server` and `location` blocks are in the same configuration file, and not split across multiple files using `include` directives.

[mjang]

Suggested change

	Make sure that the `server` and `location` blocks are in the same single configuration file, and not split across multiple files using `include` directives.
	Make sure that the `server` and `location` blocks are in the same configuration file, and not split across multiple files using `include` directives.

[mjang]

Formatting

Suggested change

	Here is an example of how to generate self-signed certificates
	Here is an example of how to generate self-signed certificates

[mjang]

Formatting

Suggested change

	openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout /etc/nginx/certs/nginx-selfsigned.key -out /etc/nginx/certs/nginx-selfsigned.crt -subj "/CN=localhost" -addext "subjectAltName=IP:127.0.0.1"
	openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout /etc/nginx/certs/nginx-selfsigned.key -out /etc/nginx/certs/nginx-selfsigned.crt -subj "/CN=localhost" -addext "subjectAltName=IP:127.0.0.1"