[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/experimental/experimental.go

@@ -0,0 +1,41 @@
+// Package experimental includes features we aren't yet sure about. These are enabled with context.Context keys.
+//
+// Note: All features here may be changed or deleted at any time, so use with caution!
+package experimental
+
+import (
+	"github.com/tetratelabs/wazero/api"
+)
+
+// InternalModule is an api.Module that exposes additional
+// information.
+type InternalModule interface {
+	api.Module
+
+	// NumGlobal returns the count of all globals in the module.
+	NumGlobal() int
+
+	// Global provides a read-only view for a given global index.
+	//
+	// The methods panics if i is out of bounds.
+	Global(i int) api.Global
+}
+
+// ProgramCounter is an opaque value representing a specific execution point in
+// a module. It is meant to be used with Function.SourceOffsetForPC and
+// StackIterator.
+type ProgramCounter uint64
+
+// InternalFunction exposes some information about a function instance.
+type InternalFunction interface {
+	// Definition provides introspection into the function's names and
+	// signature.
+	Definition() api.FunctionDefinition
+
+	// SourceOffsetForPC resolves a program counter into its corresponding
+	// offset in the Code section of the module this function belongs to.
+	// The source offset is meant to help map the function calls to their
+	// location in the original source files. Returns 0 if the offset cannot
+	// be calculated.
+	SourceOffsetForPC(pc ProgramCounter) uint64
+}