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/it.po

@@ -43,6 +43,18 @@ msgstr "Devi effettuare l'accesso per scrivere un post"
 msgid "You are not allowed to delete this blog."
 msgstr "Non sei l'autore di questo blog."
 
+#, fuzzy
+msgid "You are not allowed to edit this blog."
+msgstr "Non sei l'autore di questo blog."
+
+#, fuzzy
+msgid "You can't use this media as blog icon."
+msgstr "Non sei l'autore di questo blog."
+
+#, fuzzy
+msgid "You can't use this media as blog banner."
+msgstr "Non sei l'autore di questo blog."
+
 #, fuzzy
 msgid "You need to be logged in order to like a post"
 msgstr "Devi effettuare l'accesso per mettere mi piace ad un post"
@@ -408,6 +420,13 @@ msgstr ""
 msgid "Read the detailed rules"
 msgstr "Leggi le regole dettagliate"
 
+msgid "None"
+msgstr ""
+
+#, fuzzy
+msgid "No description"
+msgstr "Descrizione lunga"
+
 msgid "View all"
 msgstr "Vedi tutto"
 
@@ -575,9 +594,6 @@ msgstr "Lascialo vuoto se non è presente nessuno"
 msgid "Illustration"
 msgstr "Amministrazione"
 
-msgid "None"
-msgstr ""
-
 msgid "This is a draft, don't publish it yet."
 msgstr "Questa è una bozza, non pubblicarla ancora."
 
@@ -702,33 +718,30 @@ msgid "Sorry about that. If you think this is a bug, please report it."
 msgstr "Scusa per questo. Se pensi sia un bug, per favore segnalacelo."
 
 #, fuzzy
-msgid "New Blog"
-msgstr "Nuovo blog"
+msgid "Edit \"{}\""
+msgstr "Modifica"
 
-msgid "Create a blog"
-msgstr "Crea un blog"
+msgid "Description"
+msgstr "Descrizione"
 
-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 "Carica"
+
+msgid "Blog icon"
+msgstr ""
+
+msgid "Blog banner"
+msgstr ""
+
+#, fuzzy
+msgid "Update blog"
 msgstr "Crea blog"
 
-#, fuzzy
-msgid "There's one author on this blog: "
-msgid_plural "There are {0} authors on this blog: "
-msgstr[0] "Un autore in questo blog: "
-msgstr[1] "{0} autori in questo blog: "
-
-#, fuzzy
-msgid "There's one article on this blog"
-msgid_plural "There are {0} articles on this blog"
-msgstr[0] "Un articolo in questo blog"
-msgstr[1] "{0} articoli in questo blog"
-
-msgid "No posts to see here yet."
-msgstr "Nessun post da mostrare qui."
-
-msgid "New article"
-msgstr "Nuovo articolo"
-
 #, fuzzy
 msgid "Be very careful, any action taken here can't be reversed."
 msgstr ""
@@ -738,6 +751,31 @@ msgstr ""
 msgid "Permanently delete this blog"
 msgstr "Elimina questo blog"
 
+#, fuzzy
+msgid "New Blog"
+msgstr "Nuovo blog"
+
+msgid "Create a blog"
+msgstr "Crea un blog"
+
+msgid "Create blog"
+msgstr "Crea blog"
+
+msgid "{}'s icon"
+msgstr ""
+
+msgid "New article"
+msgstr "Nuovo articolo"
+
+#, fuzzy
+msgid "There's one author on this blog: "
+msgid_plural "There are {0} authors on this blog: "
+msgstr[0] "Un autore in questo blog: "
+msgstr[1] "{0} autori in questo blog: "
+
+msgid "No posts to see here yet."
+msgstr "Nessun post da mostrare qui."
+
 #, fuzzy
 msgid "Articles tagged \"{0}\""
 msgstr "Articoli etichettati \"{0}\""
@@ -766,9 +804,6 @@ msgstr ""
 msgid "Media upload"
 msgstr "Caricamento di un media"
 
-msgid "Description"
-msgstr "Descrizione"
-
 #, fuzzy
 msgid "Useful for visually impaired people, as well as licensing information"
 msgstr "Utile per persone ipovedenti e per informazioni sulla licenza"
@@ -802,6 +837,12 @@ msgstr "Copialo nei tuoi articoli per inserire questo media."
 msgid "Use as avatar"
 msgstr "Usa come avatar"
 
+#, fuzzy
+#~ msgid "There's one article on this blog"
+#~ msgid_plural "There are {0} articles on this blog"
+#~ msgstr[0] "Un articolo in questo blog"
+#~ msgstr[1] "{0} articoli in questo blog"
+
 #, fuzzy
 #~ msgid "{0}'s followers"
 #~ msgstr "Uno ti segue"