update onion engines to v3

downgrade httpx:
PR encode/httpx#1522
made some breaking changes in AsyncHTTPTransport that affect
our code in https://github.com/searx/searx/blob/master/searx/network/client.py

remove not_evil which has been down for a while now:
https://old.reddit.com/r/onions/search/?q=not+evil&restrict_sr=on&t=year

requirements.txt

@@ -7,7 +7,7 @@ lxml==4.6.3
 pygments==2.8.0
 python-dateutil==2.8.1
 pyyaml==5.4.1
-httpx[http2]==0.18.2
+httpx[http2]==0.17.1
 Brotli==1.0.9
 uvloop==0.15.2; python_version >= '3.7'
 uvloop==0.14.0; python_version < '3.7'

searx/engines/ahmia.py

@@ -9,7 +9,7 @@
 
 # about
 about = {
-    "website": 'http://msydqstlz2kzerdg.onion',
+    "website": 'http://juhanurmihxlp77nkq76byazcldy2hlmovfu2epvl5ankdibsot4csyd.onion',
     "wikidata_id": 'Q18693938',
     "official_api_documentation": None,
     "use_official_api": False,
@@ -23,7 +23,7 @@
 page_size = 10
 
 # search url
-search_url = 'http://msydqstlz2kzerdg.onion/search/?{query}'
+search_url = 'http://juhanurmihxlp77nkq76byazcldy2hlmovfu2epvl5ankdibsot4csyd.onion/search/?{query}'
 time_range_support = True
 time_range_dict = {'day': 1,
                    'week': 7,

searx/settings.yml

@@ -793,13 +793,6 @@ engines:
       require_api_key: false
       results: JSON
 
-# Requires Tor
-  - name : not evil
-    engine : not_evil
-    categories : onions
-    enable_http : True
-    shortcut : ne
-
   - name : nyaa
     engine : nyaa
     shortcut : nt