[experiment] add alternative wasm sqlite3 implementation available via build-tag (#2863)

This allows for building GoToSocial with [SQLite transpiled to WASM](https://github.com/ncruces/go-sqlite3) and accessed through [Wazero](https://wazero.io/).

vendor/github.com/tetratelabs/wazero/internal/expctxkeys/checkpoint.go

@@ -0,0 +1,10 @@
+package expctxkeys
+
+// EnableSnapshotterKey is a context key to indicate that snapshotting should be enabled.
+// The context.Context passed to a exported function invocation should have this key set
+// to a non-nil value, and host functions will be able to retrieve it using SnapshotterKey.
+type EnableSnapshotterKey struct{}
+
+// SnapshotterKey is a context key to access a Snapshotter from a host function.
+// It is only present if EnableSnapshotter was set in the function invocation context.
+type SnapshotterKey struct{}

vendor/github.com/tetratelabs/wazero/internal/expctxkeys/close.go

@@ -0,0 +1,5 @@
+package expctxkeys
+
+// CloseNotifierKey is a context.Context Value key. Its associated value should be a
+// Notifier.
+type CloseNotifierKey struct{}

vendor/github.com/tetratelabs/wazero/internal/expctxkeys/expctxkeys.go

@@ -0,0 +1,2 @@
+// Package expctxkeys provides keys for the context used to store the experimental APIs.
+package expctxkeys

vendor/github.com/tetratelabs/wazero/internal/expctxkeys/listener.go

@@ -0,0 +1,7 @@
+package expctxkeys
+
+// FunctionListenerFactoryKey is a context.Context Value key.
+// Its associated value should be a FunctionListenerFactory.
+//
+// See https://github.com/tetratelabs/wazero/issues/451
+type FunctionListenerFactoryKey struct{}

vendor/github.com/tetratelabs/wazero/internal/expctxkeys/memory.go

@@ -0,0 +1,4 @@
+package expctxkeys
+
+// MemoryAllocatorKey is a context.Context key for the experimental memory allocator.
+type MemoryAllocatorKey struct{}