betterbird: an account's own aliases and identities that do not send by SMTP share no outgoing server, and the pins name their vendors on purpose (review 36, review 35 of mesh-controller #251)

The shared-server check refused an adopted account for its own alias, and
counted Owl's, local folders' and feeds' identities as users of the default
server, though they never send by SMTP. The controller now judges an
upstream pin's host like any name, so each pin declares its vendor.

modules/betterbird/module.json

@@ -125,7 +125,10 @@
         "url": "https://www.betterbird.eu/downloads/LinuxArchive/betterbird-153.4.0esr-bb10.en-US.linux-x86_64.tar.xz",
         "sha256": "38dd24890a66b4cf9a45bc24e15192e00c26b929e1bb8df7974c16a4539129e2",
         "version": "153.4.0esr-bb10",
-        "within": "betterbird"
+        "within": "betterbird",
+        "names-on-purpose": {
+          "www.betterbird.eu": "Betterbird's project publishes its Linux release there; the build seat fetches it once, by its pinned sha256 (novox/hq ADR 0316 §2)"
+        }
       },
       {
         "name": "owl",
@@ -133,7 +136,10 @@
         "url": "https://www.beonex.com/owl/owl.xpi",
         "sha256": "a54cc3d52113b34f97942ee19190947dee23561e2217f18db3d80ac023991221",
         "version": "1.5.6.1",
-        "file": "owl.xpi"
+        "file": "owl.xpi",
+        "names-on-purpose": {
+          "www.beonex.com": "Owl's vendor publishes its xpi there; the build seat fetches it once, by its pinned sha256 (novox/hq ADR 0316 §6)"
+        }
       },
       {
         "name": "distribution",