[domscheme] Move runtime.h into a separate library

The content of tools/domschemec/runtime.h file was pasted directly to each generated .sc.h file.
Now we extract this file into LIBRARY() at library/cpp/domscheme and include it in each .sc.h in a usual way.

build/ymake.core.conf

@@ -3077,7 +3077,8 @@ macro MANUAL_GENERATION(Outs...) {
 
 # tag:src-processing
 macro _SRC("sc", SRC, SRCFLAGS...) {
-    .CMD=${tool:"tools/domschemec"} --in ${input:SRC} --out ${output;norel:SRC.h} ${output_include;hide:"util/generic/strbuf.h"} ${output_include;hide:"array"} ${output_include;hide:"util/generic/string.h"} ${output_include;hide:"util/generic/vector.h"} ${output_include;hide:"util/string/cast.h"} ${SRCFLAGS} ${kv;hide:"p SC"} ${kv;hide:"pc yellow"}
+    .CMD=${tool:"tools/domschemec"} --in ${input:SRC} --out ${output;norel:SRC.h} ${output_include;hide:"library/cpp/domscheme/runtime.h"} ${SRCFLAGS} ${kv;hide:"p SC"} ${kv;hide:"pc yellow"}
+    .PEERDIR=library/cpp/domscheme
 }
 
 # tag:src-processing