lua - move to lua as default lua engine from luajit

luajit seems to be dwindling. it also has bugs on aarch64 which means
packages for efl like i maintain on arch use lua instead of luajit by
default. reflect this as the default choice now.

README.md

@@ -347,7 +347,7 @@ Required by default:
 * openjpeg2
 * gstreamer (Ensure all codecs you want are installed.)
 * zlib
-* luajit (lua 5.1 or 5.2 support optional)
+* lua (lua 5.1, luajit or lua 5.2 support optional)
 * libtiff
 * openssl
 * curl

meson_options.txt

@@ -330,7 +330,7 @@ option('dotnet',
 option('lua-interpreter',
   type: 'combo',
   choices: ['luajit', 'lua'],
-  value: 'luajit',
+  value: 'lua',
   description: 'Which Lua back-end library to use in efl'
 )