Config.uk: Fix Kconfig dependencies

This change replaces the hard select of LIBUKMMAP and LIBNEWLIBC, using
more appropriate relationships. In addition, lib-sqlite will no longer
select itself by default.

Signed-off-by: Andrei Tatar <andrei@unikraft.io>
Reviewed-by: Maria Sfiraiala <maria.sfiraiala@gmail.com>
Reviewed-by: Stefan Jumarea <stefanjumarea02@gmail.com>
Approved-by: Razvan Deaconescu <razvand@unikraft.io>
Tested-by: Unikraft CI <monkey@unikraft.io>
GitHub-Closes: #6

Author: andreittr

Config.uk

@@ -1,9 +1,9 @@
 menuconfig LIBSQLITE
     bool "SQLite"
-    default y
-    select LIBUKMMAP
+    default n
+    imply LIBUKMMAP
     select LIBPOSIX_SYSINFO
-    select LIBNEWLIBC
+    depends on HAVE_LIBC
     select LIBPTHREAD_EMBEDDED
 
 if LIBSQLITE