Improve HTTP handling in scripts (#449)

Provide some helper methods to hide the complexity of parsing HTML, JSON, YAML, XML or Markdown.

src/visual-studio.py

@@ -1,12 +1,10 @@
-from bs4 import BeautifulSoup
 from common import dates, endoflife, http, releasedata
 
 for config in endoflife.list_configs_from_argv():
     with releasedata.ProductData(config.product) as product_data:
-        response = http.fetch_url(config.url)
-        soup = BeautifulSoup(response.text, features="html5lib")
+        html = http.fetch_html(config.url)
 
-        for table in soup.find_all("table"):
+        for table in html.find_all("table"):
             headers = [th.get_text().strip().lower() for th in table.find_all("th")]
             if "version" not in headers or "release date" not in headers:
                 continue