Edit blogs, and add blog icons and banners (#460)

Also adds a parameter to `md_to_html` to only render inline elements (so that we don't have titles or images in blog descriptions). And moves the delete button for the blog on the edition page.

I still have to update the SQLite migration once others PRs with migrations will be merged.

Also, there will be a problem when you edit a blog while not owning its banner or icon: when validating they will be reset to their default values… I don't see a good solution to this until we have a better way to handle uploads with Rocket (the same is probably happening for articles btw).

And the icon/banner are not federated yet, I don't know if I should add it to this PR or if it can come after?

![image](https://user-images.githubusercontent.com/16254623/53894510-7d853300-4030-11e9-8a2c-f5c0b0c7f512.png)
![image](https://user-images.githubusercontent.com/16254623/53894539-8b3ab880-4030-11e9-8113-685a27be8d7c.png)

Fixes #453
Fixes #454

po/plume/fr.po

@@ -47,6 +47,18 @@ msgstr "Vous devez vous connecter pour écrire un article"
 msgid "You are not allowed to delete this blog."
 msgstr "Vous n’êtes pas auteur⋅ice dans ce blog."
 
+#, fuzzy
+msgid "You are not allowed to edit this blog."
+msgstr "Vous n’êtes pas auteur⋅ice dans ce blog."
+
+#, fuzzy
+msgid "You can't use this media as blog icon."
+msgstr "Vous n’êtes pas auteur⋅ice dans ce blog."
+
+#, fuzzy
+msgid "You can't use this media as blog banner."
+msgstr "Vous n’êtes pas auteur⋅ice dans ce blog."
+
 #, fuzzy
 msgid "You need to be logged in order to like a post"
 msgstr "Vous devez vous connecter pour aimer un article"
@@ -412,6 +424,13 @@ msgstr "Accueille <em>{0} personnes"
 msgid "Read the detailed rules"
 msgstr "Lire les règles détaillées"
 
+msgid "None"
+msgstr ""
+
+#, fuzzy
+msgid "No description"
+msgstr "Description longue"
+
 msgid "View all"
 msgstr "Tout afficher"
 
@@ -572,9 +591,6 @@ msgstr "Laisser vide s’il n’y en a pas"
 msgid "Illustration"
 msgstr "Administration"
 
-msgid "None"
-msgstr ""
-
 #, fuzzy
 msgid "This is a draft, don't publish it yet."
 msgstr "Cet article n’est pas encore publié."
@@ -699,33 +715,31 @@ msgstr ""
 "signaler."
 
 #, fuzzy
-msgid "New Blog"
-msgstr "Nouveau blog"
+msgid "Edit \"{}\""
+msgstr "Modifier {0}"
 
-msgid "Create a blog"
-msgstr "Créer un blog"
+msgid "Description"
+msgstr "Description"
 
-msgid "Create blog"
+msgid ""
+"You can upload images to your gallery, to use them as blog icons or banners."
+msgstr ""
+
+#, fuzzy
+msgid "Upload images"
+msgstr "Téléverser"
+
+#, fuzzy
+msgid "Blog icon"
+msgstr "Nom du blog"
+
+msgid "Blog banner"
+msgstr ""
+
+#, fuzzy
+msgid "Update blog"
 msgstr "Créer le blog"
 
-#, fuzzy
-msgid "There's one author on this blog: "
-msgid_plural "There are {0} authors on this blog: "
-msgstr[0] "{0} auteur⋅ice dans ce blog : "
-msgstr[1] "{0} auteur⋅ice⋅s dans ce blog : "
-
-#, fuzzy
-msgid "There's one article on this blog"
-msgid_plural "There are {0} articles on this blog"
-msgstr[0] "{0} article dans ce blog"
-msgstr[1] "{0} articles dans ce blog"
-
-msgid "No posts to see here yet."
-msgstr "Aucun article pour le moment."
-
-msgid "New article"
-msgstr "Nouvel article"
-
 #, fuzzy
 msgid "Be very careful, any action taken here can't be reversed."
 msgstr ""
@@ -735,6 +749,31 @@ msgstr ""
 msgid "Permanently delete this blog"
 msgstr "Supprimer ce blog"
 
+#, fuzzy
+msgid "New Blog"
+msgstr "Nouveau blog"
+
+msgid "Create a blog"
+msgstr "Créer un blog"
+
+msgid "Create blog"
+msgstr "Créer le blog"
+
+msgid "{}'s icon"
+msgstr ""
+
+msgid "New article"
+msgstr "Nouvel article"
+
+#, fuzzy
+msgid "There's one author on this blog: "
+msgid_plural "There are {0} authors on this blog: "
+msgstr[0] "{0} auteur⋅ice dans ce blog : "
+msgstr[1] "{0} auteur⋅ice⋅s dans ce blog : "
+
+msgid "No posts to see here yet."
+msgstr "Aucun article pour le moment."
+
 #, fuzzy
 msgid "Articles tagged \"{0}\""
 msgstr "Articles taggués « {0} »"
@@ -763,9 +802,6 @@ msgstr ""
 msgid "Media upload"
 msgstr "Téléversement de média"
 
-msgid "Description"
-msgstr "Description"
-
 #, fuzzy
 msgid "Useful for visually impaired people, as well as licensing information"
 msgstr "Utile pour les personnes malvoyantes et les informations de copyright."
@@ -799,6 +835,12 @@ msgstr "Copiez-le dans vos articles pour insérer ce média."
 msgid "Use as avatar"
 msgstr "Utiliser comme avatar"
 
+#, fuzzy
+#~ msgid "There's one article on this blog"
+#~ msgid_plural "There are {0} articles on this blog"
+#~ msgstr[0] "{0} article dans ce blog"
+#~ msgstr[1] "{0} articles dans ce blog"
+
 #~ msgid "{0}'s followers"
 #~ msgstr "Abonné⋅e⋅s de {0}"