support tumblrgallery.xyz (#1298)

* support `tumblrgallery.xyz`

* fix format issues

* Refactor and add post and search page support

* Fix warnings

* Few improvments

* Better file names

* Fix linting errors

* move id closer to the begining of the file name

Co-authored-by: topozorra <none>

scripts/supportedsites.py

@@ -90,6 +90,7 @@ CATEGORY_MAP = {
     "speakerdeck"    : "Speaker Deck",
     "subscribestar"  : "SubscribeStar",
     "thebarchive"    : "The /b/ Archive",
+    "tumblrgallery"  : "TumblrGallery",
     "vanillarock"    : "もえぴりあ",
     "vsco"           : "VSCO",
     "webtoons"       : "Webtoon",