feat: add customize content type parsers for api plugin

[Josh-Walker-GM]

Alterations to #10449

[dthyresson]

Note @Josh-Walker-GM and I found that the order where custom server config was added matters - if after loading functions, then plugins like fastify complress did not work properly.

[dthyresson]

@Josh-Walker-GM I confirmed I could compress api requests:

But, graphql requests are not.

Can we add that -- or should we always compress both for api and graphql servers?

We'd still need this in createServer if the user decide to mount and server more that just the api and graphql, but we do want to let people compress graphql responses.

Also - is this a breaking change? If people use register, they will have to reconfigure their server.

[dthyresson]

@Josh-Walker-GM Should we add:

async function main() {
  const server = await createServer({
    logger,
    async configureApiServer(s) {
      await s.register(import('@fastify/compress'), {
        global: true,
        threshold: 1024,
        encodings: ['deflate', 'gzip'],
      })
    },
    async configureGraphQLServer(s) {
      await s.register(import('@fastify/compress'), {
        global: true,
        threshold: 1024,
        encodings: ['deflate', 'gzip'],
      })
    },
``` ?

In case want graphql function to handle differently?

[Josh-Walker-GM]

We can add configure graphql server too if you want. I suspected we'd want to but just kept it as api here to keep the PR small only address the issue that came up.

I don't know if I'd consider this a breaking change. Using register doesn't work and we haven't changed that behaviour - that was incorrect information on our docs to say it did. What we have done here is add in functionality to allow you do configure the server. I'd treat this is a combo of doc fix and feature addition. I might be looking at it wrong though so please push back if you think differently.

[dthyresson]

@Josh-Walker-GM sounds good I’ll make an issue for GraphQL compression as well