Add string representation to python Record object

[QuantumDancer]

I think it would be nice if we had some string implementation for Records in python.

Example:

import datetime
client = pyauditor.AuditorClientBuilder().address("127.0.0.1", 8001).build_blocking()
start_since = datetime.datetime(2023, 12, 20, 11, 30, 0, 0, tzinfo=datetime.timezone.utc)
records = client.get_stopped_since(start_since)
print(records)

This returns:

[
  <builtins.Record object at 0x7f9bc52dc0e0>,
  <builtins.Record object at 0x7f9bc52dc190>,
  <builtins.Record object at 0x7f9bc52dc240>,
  <builtins.Record object at 0x7f9bc52dc2f0>,
  ...
]

Instead, we should provide some information on the record.