runtime(sh): refactored sh.vim syntax script

- unified bashStatement, kshStatement and shStatement as much as
  possible
- separated builtin commands from external programs
- cleaned up kornshell flavor logic
- fixed alias syntax highlighting
- added test for bash alias syntax highlighting
- removed daemon keyword

closes: #18355

Signed-off-by: Bjoern Foersterling <bjoern.foersterling@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/syntax/testdir/dumps/sh_sundrous_01.dump

@@ -17,4 +17,4 @@
 |m+0#af5f00255&|k|f|i|f|o| +0#0000000&@68
 |m+0#af5f00255&|k|t|e|m|p| +0#0000000&@68
 |m+0#af5f00255&|v| +0#0000000&@72
-@57|1|9|,|1| @9|3|4|%| 
+@57|1|9|,|1| @9|3@1|%|