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_02.dump

@@ -17,4 +17,4 @@
 |s+0#af5f00255&|y|n|c| +0#0000000&@70
 |t+0#af5f00255&|a|i|l| +0#0000000&@70
 |t+0#af5f00255&|e@1| +0#0000000&@71
-@57|3|7|,|1| @9|8|1|%| 
+@57|3|7|,|1| @9|7|9|%|