introducing apm-server to elastdocker

[mostafahussein]

Signed-off-by: (╯°□°）╯︵ uᴉǝssnH ɐɟɐʇsoW mostafa.hussein91@gmail.com

What does this implement/fix? Explain your changes.

This PR will do the following:

• Add apm-server as a running container to the current stack
• Update kibana.yml with pre-configuration to add apm integration package and create a default policy for it

Does this close any currently open issues?

closes #60

Any relevant logs, error output, etc?

No

Any other comments?

The apm integration configured does not handle settings customization, not sure if it will be possible through API calls

Where has this been tested?

Ubuntu Server 22.04 LTS, verified by the points below:

• The stack is up and running
• Elastic APM integration automatically enabled on kibana
• Custom application using elastic-apm package while passing the CA certificate and secret token to be able to send events to the apm-server

[sherifabdlnaby]

@mostafahussein
Impressive! Adding APM Server has been on the TODO list of this project for quite some time! Thank you for your contribution!

Can you please add a section in README to explain how to Connect, Authenticate and Use the APM Server?

[mostafahussein]

Thank you @sherifabdlnaby .
Sure, will add a section for APM in the README file

[mostafahussein]

Hi @sherifabdlnaby ,
The README file got updated, please review it and let me know if there are any other modifications required.

[sherifabdlnaby]

@mostafahussein Thanks for your contribution! I added a small nitty change to move the APM Section to be before the Monitoring Part.