chase-symlinks: Rename chase_symlinks() to chase()

Chasing symlinks is a core function that's used in a lot of places
so it deservers a less verbose names so let's rename it to chase()
and chaseat().

We also slightly change the pattern used for the chaseat() helpers
so we get chase_and_openat() and similar.

src/basic/meson.build

@@ -14,7 +14,7 @@ basic_sources = files(
         'cap-list.c',
         'capability-util.c',
         'cgroup-util.c',
-        'chase-symlinks.c',
+        'chase.c',
         'chattr-util.c',
         'conf-files.c',
         'devnum-util.c',