Fix leftover asciidoc `[preview]` and other lifecycle markers in markdown content

[florent-leborgne]

Example: https://www.elastic.co/docs/explore-analyze/visualize/custom-visualizations-with-vega#vega-esmfiles

These are still following the asciidoc syntax and as a consequence are not rendered properly. They should be updated to follow the markdown corresponding syntax for feature lifecycles.

This was reported in Explore & Analyze but we should look for remaining occurrences everywhere

[colleenmcginnis]

Might be worth replacing deprecated, added, coming, experimental, and beta while we're at it. 🙂 A quick search returns ~200 results in 129 files across the following repos:

• - apm-agent-java [Docs] Convert asciidoc lifecycle markers into Docs V3 syntax apm-agent-java#4225
• - apm-aws-lambda [Docs] Convert asciidoc lifecycle markers into Docs V3 syntax apm-aws-lambda#709
• - apm-k8s-attacher [Docs] Convert asciidoc lifecycle markers into Docs V3 syntax apm-k8s-attacher#170
• - beats [Docs] Convert asciidoc lifecycle markers into Docs V3 syntax beats#46754
• - docs-content Replace leftover asciidoc lifecycle markers with applies_to #3143
• - elastic-serverless-forwarder [Docs] Convert asciidoc lifecycle markers into Docs V3 syntax elastic-serverless-forwarder#983
• - elasticsearch [Docs] Convert asciidoc lifecycle markers into Docs V3 syntax elasticsearch#135347
• - integration-docs - skipping, few occurrences not worth the effort
• - integrations - skipping, few occurrences not worth the effort
• - kibana [Docs] Convert asciidoc lifecycle markers into new syntax kibana#236292

Regex:

(\[(preview|beta|experimental|dev|deprecated|added|coming)\]|(preview|beta|experimental|dev|deprecated|added|coming):*\[)