Add searx_extra package

Split the utils directory into:
* searx_extra contains update scripts, standalone_searx.py
* utils contains the files to build and setup searx.

utils/fetch_firefox_version.py

@@ -1,73 +0,0 @@
-#!/usr/bin/env python
-
-# set path
-from sys import path
-from os.path import realpath, dirname, join
-path.append(realpath(dirname(realpath(__file__)) + '/../'))
-
-#
-import json
-import requests
-import re
-from urllib.parse import urlparse, urljoin
-from distutils.version import LooseVersion, StrictVersion
-from lxml import html
-from searx import searx_dir
-
-URL = 'https://ftp.mozilla.org/pub/firefox/releases/'
-RELEASE_PATH = '/pub/firefox/releases/'
-
-NORMAL_REGEX = re.compile('^[0-9]+\.[0-9](\.[0-9])?$')
-# BETA_REGEX = re.compile('.*[0-9]b([0-9\-a-z]+)$')
-# ESR_REGEX = re.compile('^[0-9]+\.[0-9](\.[0-9])?esr$')
-
-# 
-useragents = {
-    "versions": (),
-    "os": ('Windows NT 10.0; WOW64',
-           'X11; Linux x86_64'),
-    "ua": "Mozilla/5.0 ({os}; rv:{version}) Gecko/20100101 Firefox/{version}"
-}
-
-
-def fetch_firefox_versions():
-    resp = requests.get(URL, timeout=2.0)
-    if resp.status_code != 200:
-        raise Exception("Error fetching firefox versions, HTTP code " + resp.status_code)
-    else:
-        dom = html.fromstring(resp.text)
-        versions = []
-
-        for link in dom.xpath('//a/@href'):
-            url = urlparse(urljoin(URL, link))
-            path = url.path
-            if path.startswith(RELEASE_PATH):
-                version = path[len(RELEASE_PATH):-1]
-                if NORMAL_REGEX.match(version):
-                    versions.append(LooseVersion(version))
-
-        list.sort(versions, reverse=True)
-        return versions
-
-
-def fetch_firefox_last_versions():
-    versions = fetch_firefox_versions()
-
-    result = []
-    major_last = versions[0].version[0]
-    major_list = (major_last, major_last - 1)
-    for version in versions:
-        major_current = version.version[0]
-        if major_current in major_list:
-            result.append(version.vstring)
-
-    return result
-
-
-def get_useragents_filename():
-    return join(join(searx_dir, "data"), "useragents.json")
-
-
-useragents["versions"] = fetch_firefox_last_versions()
-with open(get_useragents_filename(), "w") as f:
-    json.dump(useragents, f, indent=4, ensure_ascii=False)