[8.x](backport #41934) [filebeat][streaming] - Added support for TLS & forward proxy configs for websockets

[mergify]

Type of change

• Enhancement
• Docs

Proposed commit message

Added support for functional TLS config & proxy configs for websockets by implementing a custom transport object and NetDialContext() and leveraging the httpcommon library. Added supporting tests to accompany

Note:

Tried using in memory certs and keys but our current httpcommon library always asks for a file.

Checklist

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding change to the default configuration files
• I have added tests that prove my fix is effective or that my feature works
• I have added an entry in CHANGELOG.next.asciidoc or CHANGELOG-developer.next.asciidoc.

Disruptive User Impact

No enduser impact as this is all additive.

Author's Checklist

• [ ]

How to test this PR locally

Related issues

• Closes
• Relates [Proofpoint On Demand] Investigate adding forward proxy support integrations#11581

Use cases

Screenshots

Logs

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This is an automatic backport of pull request #41934 done by [Mergify](https://mergify.com).

[botelastic]

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