treewide: mark things static and const

Mark some structures, arrays static/const at various places.
In some cases this prevents unnecessary initialization
when a function is entered.

All in all, the text segments across all shared
libraries are reduced by about 2 KiB. However,
the total size increases by about 2 KiB as well.

src/modules/module-protocol-native/v0/typemap.h

@@ -1,5 +1,4 @@
-
-const struct type_info {
+static const struct type_info {
 	const char *type;
 	const char *name;
 	uint32_t id;