chore: drop three reads whose result went nowhere

The requirement parser read core, hashMatchMandatory and note from
each bios element and discarded all three, which reads like a dropped
attribute: hashMatchMandatory decides whether a wrong hash is yellow or
red on Recalbox. It is not lost -- the config parser below captures it
for the YAML -- so these were leftovers, and they cost a look to
confirm that.

Two yaml imports left unused by the move to the shared loader go too.

scripts/scraper/_hash_merge.py

@@ -13,7 +13,6 @@ import shutil
 from pathlib import Path
 from typing import Any
 
-import yaml
 
 from common import yaml_load
 

scripts/scraper/batocera_scraper.py

@@ -16,7 +16,6 @@ import urllib.error
 import urllib.request
 from pathlib import Path
 
-import yaml
 
 from common import yaml_load
 

scripts/scraper/recalbox_scraper.py

@@ -140,10 +140,7 @@ class Scraper(BaseScraper):
             for bios_elem in system_elem.findall("bios"):
                 paths_str = bios_elem.get("path", "")
                 md5_str = bios_elem.get("md5", "")
-                bios_elem.get("core", "")
                 mandatory = bios_elem.get("mandatory", "true") != "false"
-                bios_elem.get("hashMatchMandatory", "true") != "false"
-                bios_elem.get("note", "")
 
                 paths = [p.strip() for p in paths_str.split("|") if p.strip()]
                 if not paths: