Doc: Evaluate and action Beats module messaging and deprecation

Current offerings -- [Elastic Agent](https://www.elastic.co/guide/en/fleet/current/index.html), [Elastic integrations](https://www.elastic.co/docs/current/integrations), and the [logstash-filter-agent_integration](https://www.elastic.co/guide/en/logstash/master/ea-integrations.html -- might give users better ways to achieve the same results.

### Phase 1: Evaluate recommendations
@flexitrev @jsvd @robbavey @karenzone

#### Filebeat modules
- [ ] https://www.elastic.co/guide/en/logstash/master/filebeat-modules.html

#### Winlogbeat modules
- [ ] https://www.elastic.co/guide/en/logstash/master/winlogbeat-modules.html

### Phase 2: Implement recommendations
@karenzone et al

Related: #16590