Import upstream v0.16.22, stripped

Upstream commit: 474dd0229cb20cf513036619781ed97bd8073c3f
Enterprise-only files removed or emptied: 63
Enterprise-only snippets removed: 117 in 50 files
Dangling module declarations removed: 5
Cargo edits turning enterprise off: 14
Verification: clean
Enterprise feature gates left for rebuilt features: 19 in 18 files

Produced by tools/fork/strip.py. The full report is in docs/fork/strip-reports/ on main.

crates/store/src/backend/ephemeral/mod.rs

@@ -0,0 +1,22 @@
+/*
+ * SPDX-FileCopyrightText: 2020 Stalwart Labs LLC <[email protected]>
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-SEL
+ */
+
+pub mod blob;
+pub mod main;
+pub mod read;
+pub mod write;
+
+use ahash::AHashMap;
+use parking_lot::RwLock;
+use std::collections::BTreeMap;
+
+pub struct EphemeralStore {
+    pub(crate) state: RwLock<EphemeralState>,
+}
+
+pub(crate) struct EphemeralState {
+    pub(crate) subspaces: AHashMap<u8, BTreeMap<Vec<u8>, Vec<u8>>>,
+}