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_03.dump

@@ -5,7 +5,8 @@
 |u+0#af5f00255&|n|i|q| +0#0000000&@70
 >w+0#af5f00255&|c| +0#0000000&@72
 |x+0#af5f00255&|a|r|g|s| +0#0000000&@69
-|x+0#af5f00255&|g|r|e|p| +0#0000000&@69
+|#+0#0000e05&| |x|g|r|e|p| |i|s| |n|e|i|t|h|e|r| |a| |b|u|i|l|t|i|n| |f|o|r| |b|a|s|h| |n|o|r| |a|n| |e|x|t|e|r|n|a|l| |p|r|o|g|r|a|m| +0#0000000&@13
+|x|g|r|e|p| @69
 |~+0#4040ff13&| @73
 |~| @73
 |~| @73
@@ -16,5 +17,4 @@
 |~| @73
 |~| @73
 |~| @73
-|~| @73
 | +0#0000000&@56|5@1|,|1| @9|B|o|t|