System requirements update elasticsearch/opensearch needed

[chriz-uniba]

The following lines need some update wrt. opensearch:

docs-invenio-rdm/docs/install/requirements.md

Lines 45 to 48 in 4e96e2e

	!!! note "Elasticsearch vs OpenSearch"
	InvenioRDM will be transitioning from Elasticsearch to OpenSearch due to license changes in Elasticsearch which means it is no longer an open source product. We are currently assessing if it is feasible from a technical and resource perspective to support both products.

[chriz-uniba]

Also here:

docs-invenio-rdm/docs/install/requirements.md

Lines 96 to 115 in 4e96e2e

	#### Elasticsearch and Docker (macOS and Linux)
	Among the containers you will run is an Elasticsearch container which is quite demanding.
	Per Elasticsearch's [Docker documentation](https://www.elastic.co/guide/en/elasticsearch/reference/7.9/docker.html#docker-prod-prerequisites),
	you will want to apply the following kernel setting:
	On Linux, add the following to ``/etc/sysctl.conf`` on your local machine (host machine):
	```bash
	# Maximum number of memory map areas a process (Elasticsearch) may have
	vm.max_map_count=262144
	```
	On macOS, do the following:
	```bash
	screen ~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/tty
	# and in the shell
	sysctl -w vm.max_map_count=262144
	```

[psaiz]

I have the feeling that this was addressed in #551
@kpsherva, would you mind confirming it?

[psaiz]

So, the first comment was indeed already addressed. The second one, about the requirements is not. Thanks for pointing this out!
I'll send a new PR to address it