[8.15] Makes inference endpoint the primary way to download and deploy ELSER and E5 (backport #2765)

[mergify]

Overview

This PR overhauls the ELSER and E5 conceptual pages:

• indicates that the recommended and easiest way to download and deploy the models is using inference endpoints,
• introduces the procedure of creating an inference endpoint in the Download and deploy section,
• makes the alternative download and deploy methods less prominent by putting them into collapsible sections that are closed by default,
• propagates the semantic_text workflow for semantic search.

Preview

• ELSER
• E5

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  This is an automatic backport of pull request Makes inference endpoint the primary way to download and deploy ELSER and E5 #2765 done by Mergify.

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