Masked email: upstream's x:MaskedEmail API (ME-2, ME-3, ME-6a, ME-7a, ME-12 to ME-19)

x:MaskedEmail is no longer refused as unbuilt. Creates generate the address
on an allowed domain and check the prefix, maxMaskedAddresses and the create
rate; updates keep server-set fields; enabled reads and writes map to the
shared state; query filters on enabled, forDomain and text; a tenant
administrator reaches its tenant's accounts' masks.

crates/jmap/src/lib.rs

@@ -33,6 +33,7 @@ pub mod contact;
 pub mod email;
 pub mod file;
 pub mod identity;
+pub mod inbuxa; // inbuxa: the fork's own features
 pub mod mailbox;
 pub mod participant_identity;
 pub mod principal;