[WIP] Rewrite to Proxy class: (#5507)

* Rewrite to Proxy class:
- introduced new Friendica\Network\Proxy class for in exchange of proxy_*()
  functions
- moved also all PROXY_* constants there as Proxy::*
- removed now no longer needed mod/proxy.php loading as composer's auto-load
  will do this for us
- renamed those proxy_*() functions to better names:
  + proxy_init()           -> Proxy::init()         (public)
  + proxy_url()            -> Proxy::proxifyUrl()   (public)
  + proxy_parse_html()     -> Proxy::proxifyHtml()  (public)
  + proxy_is_local_image() -> Proxy::isLocalImage() (private)
  + proxy_parse_query()    -> Proxy::parseQuery()   (private)
  + proxy_img_cb()         -> Proxy::replaceUrl()   (private)

* Ops, need to set $a here ...

* CR request:
- moved Proxy class to Friendica\Module
- extended BaseModule

* Ops, no need for own instance of $a when self::getApp() is around.

* Proxy-rewrite:
- proxy_url() and proxy_parse_html() are both non-module functions (now
  methods)
- so they must be splitted into a seperate class
- also the SIZE_* and DEFAULT_TIME constants are both not relevant to module

* No instances from utility classes

* Fixed error:
- proxify*() is now located in `Friendica\Util\ProxyUtils`

* Moved back to original place, ops? How did they move here? Well, it was not
intended by me.

* Removed duplicate (left-over from split) constants and static array. Thank to
MrPetovan finding it.

* Renamed ProxyUtils -> Proxy and aliased it back to ProxyUtils.

mod/acl.php

@@ -9,9 +9,9 @@ use Friendica\Core\Addon;
 use Friendica\Database\DBA;
 use Friendica\Model\Contact;
 use Friendica\Model\Item;
+use Friendica\Util\Proxy as ProxyUtils;
 
 require_once 'include/dba.php';
-require_once 'mod/proxy.php';
 
 function acl_content(App $a)
 {
@@ -192,7 +192,7 @@ function acl_content(App $a)
 		$contacts = [];
 		foreach ($r as $g) {
 			$contacts[] = [
-				'photo'   => proxy_url($g['photo'], false, PROXY_SIZE_MICRO),
+				'photo'   => ProxyUtils::proxifyUrl($g['photo'], false, ProxyUtils::SIZE_MICRO),
 				'name'    => $g['name'],
 				'nick'    => defaults($g, 'addr', $g['url']),
 				'network' => $g['network'],
@@ -214,7 +214,7 @@ function acl_content(App $a)
 		foreach ($r as $g) {
 			$entry = [
 				'type'    => 'c',
-				'photo'   => proxy_url($g['micro'], false, PROXY_SIZE_MICRO),
+				'photo'   => ProxyUtils::proxifyUrl($g['micro'], false, ProxyUtils::SIZE_MICRO),
 				'name'    => htmlentities($g['name']),
 				'id'      => intval($g['id']),
 				'network' => $g['network'],
@@ -275,7 +275,7 @@ function acl_content(App $a)
 			if (count($contact) > 0) {
 				$unknown_contacts[] = [
 					'type'    => 'c',
-					'photo'   => proxy_url($contact['micro'], false, PROXY_SIZE_MICRO),
+					'photo'   => ProxyUtils::proxifyUrl($contact['micro'], false, ProxyUtils::SIZE_MICRO),
 					'name'    => htmlentities($contact['name']),
 					'id'      => intval($contact['cid']),
 					'network' => $contact['network'],