Remove Elasticsearch setup, default to waiting for data streams to be set up

[simitt]

Follow up on #5914

In 7.x an option is introduced to wait for data streams to be set up before writing to data streams. The option is disabled by default. When this option is enabled, APM Server waits for the integration package to be installed before writing any data.

In 8.0 we will

• remove the ability to setup Elasticsearch
• always write to data streams (remove option)
• turn the option to wait for data streams to be set up on by default. It should still be possible to disable the option for scenarios where APM Server lacks privileges to check the package is installed; in this case the user is responsible for ensuring the package is installed before APM Server is started.