fix: refactor request params to use generics

[kangmingtay]

What kind of change does this PR introduce?

• Introduce a new method retrieveRequestParams which makes use of generics to parse a request
• This will help to simplify parsing a request from:

params := RequestParams{}
body, err := getBodyBytes(r)
if err != nil {
  return nil, badRequestError("Could not read body").WithInternalError(err)
}

if err := json.Unmarshal(body, &params); err != nil {
  return nil, badRequestError("Could not decode request params: %v", err)
}

to

params := &Request{}
err := retrieveRequestParams(req, params)

TODO

• Add type constraint instead of using any