Deprecate the nu_scripts version of stdlib-candidate (#1042)

Deprecates the existing `stdlib-candidate` directories in `nu_scripts`
since `std-rfc` has now transitioned to the main repo. Updates readme
and renamed directories.

stdlib-candidate-archive/stdlib-candidate-older/std-rfc/bulk-rename.nu

@@ -0,0 +1,49 @@
+# Rename bulk input files in parallel using a closure.
+#
+# The reason behind this command is quite simple:
+# - Sometimes one receives a bunch of files with integer ids: 1, 2, 3, ...
+# - These ids come rarely with padding... i.e. 1 instead of 001 when there are 3-digit ids
+# - This means that file with id 9 will be sorted way after file with id 1000
+#
+# This command allows to do such a task!
+#
+# Examples:
+#   Rename `.mise.toml` files to `.mise.local.toml` recursively
+#   > glob **/.mise.toml | bulk-rename { str append .local }
+#
+#   Rename files in `/foo` with a name that has an id to have 3 digits with 0-padding
+#   > ls /foo | bulk-rename { |path|
+#      if $path.input.type == file {
+#        $path.stem | parse "some_format_{id}"
+#          | get 0
+#          | update id { fill --alignment r --character 0 --width 3 }
+#          | $"some_format_($in.id)"
+#      }
+#      # else skip dirs
+#    }
+export def main [
+    update_stem: closure, # The code to rename the file stem: receives the old stem as input and a record param with both `stem` and `input` keys
+    --verbose (-v), # Show which files were renamed, if any
+    --no-execute (-n) # Do not make any changes; add --verbose to see what would be made
+]: [list<any> -> nothing, list<any> -> table<old: path new: path>] {
+    let renamed = par-each --keep-order { |input|
+        let update_or_keep_stem = { |parts|
+            do $update_stem { stem: $in input: $input } | default $parts.stem
+        }
+        let old = if ($input | describe) == string {
+            $input
+        } else {
+            $input.name # convenience for ls
+        }
+        let new = $old | path parse | update stem $update_or_keep_stem | path join
+        if $new != $old {
+            if not $no_execute {
+                mv --force --verbose=$verbose $old $new
+            }
+            { old: $old new: $new }
+        }
+    }
+    if $verbose {
+        $renamed
+    }
+}