in_opentelemetry: add proto files for logs

[Syn3rman]

Adds support for ingesting OpenTelemetry logs into Fluent Bit (both JSON and protobuf encoded payloads)

Addresses #5779

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Testing
Before we can approve your change; please submit the following in a comment:

• Example configuration file for the change

[INPUT]
  name opentelemetry
  host 0.0.0.0
  port 4318

[OUTPUT]
  name stdout
  match *

• Debug log output from testing the change

• Attached Valgrind output that shows no leaks or memory corruption was found

If this is a change to packaging of containers or native binaries then please confirm it works for all targets.

• Attached local packaging test output showing all targets (including any new ones) build.

Documentation

• Documentation required for this feature
  pipeline: inputs: opentelemetry: add docs fluent-bit-docs#872

Backporting

• Backport to latest stable release.

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Fluent Bit is licensed under Apache 2.0, by submitting this pull request I understand that this code will be released under the terms of that license.