Update a contact on re-import rather than skipping it

#228 skipped a vCard whose UID the book already held. The reporter asked for
the opposite on #174 and he is right: the reason to import a file a second
time is usually that the first one was not right, so skipping means a
corrected export corrects nothing.

A merge, not a replacement. Properties the file carries overwrite what is
here; properties it does not mention are left alone, so a phone number added
in ihasmail after the first import survives a re-import of the original file.
The cost is that a field genuinely deleted at the source stays here, which is
the better way to be wrong -- the other way round loses work nobody asked to
lose. Worth confirming with him rather than assuming.

`addressBookIds` is left off the patch. The card is already in this book, so
saying it again says nothing, and saying it on a card that is also in another
book would move it.

Creates and updates now share one batch budget. Stalwart counts every object
in a /set together, so batching the halves separately would send 300 new and
300 changed as two calls of 300 and be refused for a limit of 500 that neither
half exceeds.

LDIF is untouched and still reports look-alikes without acting on them, since
what it should match on is the question still open on #223. Both imports keep
one answer shape so a caller need not know which it called; LDIF's `updated`
is always 0, which is the honest number rather than a missing field.

The message a vCard attached to a message shows changes with it: the newer
copy now wins instead of being dropped, so it says the contact was brought up
to date rather than that nothing was added.

Refs #223.

web/src/locales/es.ts

@@ -1053,10 +1053,11 @@ export const catalog: Catalog = {
     "Nothing unread here": "Aquí no hay nada sin leer",
   },
   plurals: {
+    "Updated {n} contacts, nothing new": { one: "{n} contacto actualizado, nada nuevo", other: "{n} contactos actualizados, nada nuevo" },
+    "{n} updated": { one: "{n} actualizado", other: "{n} actualizados" },
+    "Updated {n} contacts you already had": { one: "Se actualizó el contacto que ya tenías", other: "Se actualizaron {n} contactos que ya tenías" },
     "{n} of them look like contacts you already had": { one: "{n} de ellos se parece a un contacto que ya tenías", other: "{n} de ellos se parecen a contactos que ya tenías" },
     "Your administrator changed {n} settings": { one: "Tu administración cambió {n} ajuste", other: "Tu administración cambió {n} ajustes" },
-    "Already here: {n} contacts, nothing imported": { one: "Ya estaba aquí: {n} contacto, no se importó nada", other: "Ya estaban aquí: {n} contactos, no se importó nada" },
-    "All {n} are already in your contacts": { one: "Ya está en tus contactos", other: "Los {n} ya están en tus contactos" },
     "Exported {n} events": { one: "{n} evento exportado", other: "{n} eventos exportados" },
     "Imported {n} events": { one: "{n} evento importado", other: "{n} eventos importados" },
     "Already here: {n} events, nothing imported": { one: "Ya estaba aquí: {n} evento, no se importó nada", other: "Ya estaban aquí: {n} eventos, no se importó nada" },