Move logging logic to singleton

- Renamed module and class because "conductor" didn't make a lot of sense
- Used singleton approach (there's only one stdout after all)
- Redesigned progress bars (now with download speed!)

PFERD/crawlers/__init__.py

@@ -2,7 +2,6 @@ from configparser import SectionProxy
 from typing import Callable, Dict
 
 from ..authenticator import Authenticator
-from ..conductor import TerminalConductor
 from ..config import Config
 from ..crawler import Crawler
 from .ilias import KitIliasCrawler, KitIliasCrawlerSection
@@ -12,13 +11,12 @@ CrawlerConstructor = Callable[[
     str,                       # Name (without the "crawl:" prefix)
     SectionProxy,              # Crawler's section of global config
     Config,                    # Global config
-    TerminalConductor,         # Global conductor instance
     Dict[str, Authenticator],  # Loaded authenticators by name
 ], Crawler]
 
 CRAWLERS: Dict[str, CrawlerConstructor] = {
-    "local": lambda n, s, c, t, a:
-        LocalCrawler(n, LocalCrawlerSection(s), c, t),
-    "kit-ilias": lambda n, s, c, t, a:
-        KitIliasCrawler(n, KitIliasCrawlerSection(s), c, t, a),
+    "local": lambda n, s, c, a:
+        LocalCrawler(n, LocalCrawlerSection(s), c),
+    "kit-ilias": lambda n, s, c, a:
+        KitIliasCrawler(n, KitIliasCrawlerSection(s), c, a),
 }