Directory: Use Serde encoded data instead of just String

[wthrajat]

In src/market/rpc/server.rs, the handle_client() is using raw string parsing for communication. This PR aims to fix it:

• Use serde for structured data communication instead of raw strings.
• Added timeouts to the TcpStream using set_read_timeout() and set_write_timeout() to ensure that the server does not hang indefinitely while waiting for data.
• Introduced one new enum and one new struct:

Request: Handles Post and Get operations from 
Response: Encodes the list of addresses as a JSON response.

• Added appropriate logging for both Post and Get operations
• Improve stream handling using BufReader and BufWriter for better I/O operations.
• JSON encoding/decoding replaces raw string operations for safer and clearer data handling.
• Fix tests

[Shourya742]

It makes sense to have a Request enum and a Response struct. However, I don’t see any changes in the taker for handling the new serialized format, which could potentially lead to test failures. While using BufWriter makes sense to reduce syscalls, in our case, we're only using the stream for a single write call, so batching writes won’t provide much benefit and will result in similar complexity. That said, the changes look good overall. Just ensure that the taker is handled properly, and double-check if the directory-cli app is functioning correctly.

[wthrajat]

@Shourya742 Yes it was still supposed to be a draft now. Forgot to change the status.

[mojoX911]

Will be solved later.