Packaging: the binary and package are inbuxa, INBUXA_* settings with STALWART_* fallback

- crates/main: package and [[bin]] renamed to inbuxa; homepage inbuxa.org;
  license AGPL-3.0-only (upstream is dual; the fork takes the AGPL).
- types::branding::env_var reads INBUXA_<name>, falling back to
  STALWART_<name> with a warning, for all nine server settings.
  STALWART_APP_ and STALWART_SPAM_* storage keys are unchanged.
- New-install default paths /var/lib/inbuxa and /var/log/inbuxa.
- Dockerfiles, systemd unit, launchd plist and AppArmor profile renamed.
- Upstream's .github moved to .github-upstream so none of it runs.
- install.sh stubbed: upstream's would install Stalwart.
- Two missed brand strings: the SMTP Received header and the utils user agent.

crates/jmap/src/registry/mapping/bootstrap.rs

@@ -657,7 +657,7 @@ fn map_dns_server(dns_server: &DnsServerBootstrap) -> Option<registry::schema::s
 const DEFAULT_DATA_PATH: &str = if cfg!(target_os = "freebsd") {
     "/var/db/stalwart/"
 } else {
-    "/var/lib/stalwart/"
+    "/var/lib/inbuxa/"
 };
 
 fn build_default_bootstrap(server: &Server) -> Bootstrap {
@@ -676,7 +676,7 @@ fn build_default_bootstrap(server: &Server) -> Bootstrap {
         in_memory_store: InMemoryStore::Default,
         directory: DirectoryBootstrap::Internal,
         tracer: Tracer::Log(TracerLog {
-            path: "/var/log/stalwart/".to_string(),
+            path: "/var/log/inbuxa/".to_string(),
             prefix: "stalwart".to_string(),
             ansi: true,
             enable: true,