Change the path for HTTP source

[dlvenable]

Is your feature request related to a problem? Please describe.

The http source always uses the path log/ingest.

Describe the solution you'd like

Provide a configure to allow a pipeline author to change this path.

source:
  http:
    path: my/unique/path
    ssl: true
    ssl_certificate_file: "/full/path/to/certfile.crt"
    ssl_key_file: "/full/path/to/keyfile.key"

With that configuration, the HTTP source will be available at:

https://localhost:2021/my/unique/path

Describe alternatives you've considered (Optional)

This could use prefix, but I don't see a reason to require the log/ingest. Unlike OTel, this is not a convention.

Additional context

This is somewhat similar to #2257, but this is for the http source only. It is quite different from the OTel sources.

[dlvenable]

Also include a ${pipelineName} variable to allow using the pipelineName as part of the path.