refactor(Service): Go back to the default pool_maxsize in Session

The pool_maxsize value here isn't actually doing much. It should have also been applied to pool_connections. What we realistically needed was just pool_block to prevent opening too much connections (causing a warning). The default pool_connections=10 and pool_maxsize=10 is fine. The downloader doesn't currently use this value.

devine/core/service.py

@@ -98,9 +98,6 @@ class Service(metaclass=ABCMeta):
                 backoff_factor=0.2,
                 status_forcelist=[429, 500, 502, 503, 504]
             ),
-            # 16 connections is used for byte-ranged downloads
-            # double it to allow for 16 non-related connections
-            pool_maxsize=16 * 2,
             pool_block=True
         ))
         session.mount("http://", session.adapters["https://"])