feat: basic but generic http parser

[Autoparallel]

This HTTP parsing can tell you when you are on the start line, in headers, or in the body. It does so with 3 flags:

• parsing_start: Equals 1 if we are parsing the start line (either method / status), 0 otherwise.
• parsing_header: Equals 1 if we are parsing headers, 0 otherwise.
• parsing_body: Equals 1 if we are parsing body, 0 otherwise.

Tested this with the circuits:

    "get_request": {
        "file": "http/parser/parser",
        "template": "Parser",
        "params": [60]
    },
    "get_response": {
        "file": "http/parser/parser",
        "template": "Parser",
        "params": [89]
    }

You can get the necessary witness files by running:

witness http --input-file examples/http/get_request.http --output-dir inputs/get_request --output-filename input.json
witness http --input-file examples/http/get_response.http --output-dir inputs/get_response --output-filename input.json

Note, I had to do some jank in the rust witnessgen that prepends a CL char since I couldn't get this in the file another way. However that works for now!

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Closes #58

[lonerapier]

cooking never ends!!