Add HTTP/1 max header size limit

[myyrakle]

Is your feature request related to a problem? Please describe.
I need "the ability to limit the size of Request Header".
Although it is possible to implement this in an application, I think it is most efficient if it can be handled at the protocol implementation level.

Describe the solution you'd like
Currently, it is supported to specify the number of headers through the "h1_max_headers" option when creating a builder. I think it would be okay to control it by adding a few properties like this.

Describe alternatives you've considered
If we implement the header max setting, there may be several ways to do this.

1. number of header: already implemented
2. max size of each heade name: Fixed at 64kb
3. max size of each heade value: none (maybe)
4. max size of total header: none

What if all of this could be set as a builder option? What do you think about this?

Question
If the problem was simple, I would implement it myself and post a PR, but a question arose while looking at the code.

There is evidence of an attempt to add an option called "h1_max_header_size". What exactly is the max that this is trying to implement?

[vcschapp]

It would be nice to be able to control the max size of the head of the message (start line plus header block) or more granularly max size of the start line as one parameter and max size of the header block as a second parameter.

There are cases where I might want to keep a large max_buf_size but still fail fast in the event that the start line or header block seems to be maliciously large...

[seanmonstar]

Yes, it'd be welcome to add a general max_header_size(bytes) option. I don't lean towards more granularity, I see the start line as part of the headers, especially since they truly are in HTTP/2 and 3.