Expose user avatar URL field in the UI (#27)

* wip

* some fixes

* update readme

* update readme

* Add option to change/erase any user's avatar

* Fix README

* Remove mutationMode from Edit

* remove log

* update readme

src/i18n/de.ts

@@ -147,6 +147,7 @@ const de: SynapseTranslationMessages = {
       },
       action: {
         erase: "Lösche Benutzerdaten",
+        erase_avatar: "Avatar löschen"
       },
     },
     rooms: {

src/i18n/en.ts

@@ -146,6 +146,7 @@ const en: SynapseTranslationMessages = {
       },
       action: {
         erase: "Erase user data",
+        erase_avatar: "Erase avatar"
       },
     },
     rooms: {

src/i18n/fr.ts

@@ -144,6 +144,7 @@ const fr: SynapseTranslationMessages = {
       },
       action: {
         erase: "Effacer les données de l'utilisateur",
+        erase_avatar: "Effacer l'avatar",
       },
     },
     rooms: {

src/i18n/index.d.ts

@@ -142,6 +142,7 @@ interface SynapseTranslationMessages extends TranslationMessages {
       };
       action: {
         erase: string;
+        erase_avatar: string;
       };
     };
     rooms: {

src/i18n/ru.ts

@@ -155,6 +155,7 @@ const ru: SynapseTranslationMessages = {
       },
       action: {
         erase: "Удалить данные пользователя",
+        erase_avatar: "Удалить аватар",
       },
     },
     rooms: {

src/i18n/zh.ts

@@ -139,6 +139,7 @@ const zh: SynapseTranslationMessages = {
       },
       action: {
         erase: "抹除用户信息",
+        erase_avatar: "抹掉头像",
       },
     },
     rooms: {