plugin XEP-0264: replace SIZE_FULL_SCREEN by SIZE_BIG:

`SIZE_FULL_SCREEN` may result in large files, and BoB is currently used to transfer them,
resulting in potentially large stanza. As a result, Libervia profile can be disconnected
from server if stanza max size is reached.

As a temporary workaround, `SIZE_BIG` is now the maximum size used. This should be fixed
in 0.9 with a proper way to transfer large thumbnails (i.e. not BoB).

sat/plugins/plugin_xep_0264.py

@@ -73,7 +73,10 @@ class XEP_0264(object):
     SIZE_MEDIUM = (640, 640)
     SIZE_BIG = (1280, 1280)
     SIZE_FULL_SCREEN = (2560, 2560)
-    SIZES = (SIZE_SMALL, SIZE_MEDIUM, SIZE_FULL_SCREEN)
+    # FIXME: SIZE_FULL_SCREEN is currently discarded as the resulting files are too big
+    # for BoB
+    # TODO: use an other mechanism than BoB for bigger files
+    SIZES = (SIZE_SMALL, SIZE_MEDIUM, SIZE_BIG)
 
     def __init__(self, host):
         log.info(_("Plugin XEP_0264 initialization"))