Make Robyn more modularized

[i1619khz]

Hi, @sansyrox, I noticed the fixed Public RoadMap for issues and would like to make a few suggestions. Could we consider removing the default internal implementation of jsonify and instead modify it to an extension interface with additional extension modules to achieve better extensibility? I might need better performance and wish to replace the default orjson with msgspec. Since msgspec also includes validation features similar to pydantic, if we can combine these through abstract interfaces + extension implementations, it would result in a cleaner list of component dependencies compared to default integration. This approach would also avoid confusion caused by multiple libraries having overlapping functionalities. We could extend this into something like the following:

• robyn-jsonify-orjson
• robyn-jsonify-msgspec
• robyn-serde-msgspec
• robyn-serde-pydantic