file: add file_name attribute to DeploymentTrash

Fixes #209
See FC-42677

This won't work for multiple deployments on the same host using all the
same file since all of those deployments will override each other's
trash.nix (or fail trying if each deployment uses its own service user).

src/batou_ext/file.py

@@ -42,6 +42,7 @@ class SymlinkAndCleanup(batou.component.Component):
     systemd_read_max_iops = 100
     systemd_write_max_iops = 100
     trashdir = None
+    trash_config_file_name = Attribute(str, default="trash.nix")
 
     ## DEPRECATED, do not use
     use_systemd_run_async_cleanup = False
@@ -58,6 +59,7 @@ def configure(self):
             read_iops_limit=self.systemd_read_max_iops,
             write_iops_limit=self.systemd_write_max_iops,
             trashdir=self.trashdir,
+            file_name=self.trash_config_file_name,
         )
         self.trash = self._
 
@@ -170,6 +172,8 @@ def update(self):
     ```
     """
 
+    file_name = Attribute(str, default="trash.nix")
+
     read_iops_limit = 100
     write_iops_limit = 100
 
@@ -181,7 +185,7 @@ def configure(self):
 
         self += batou.lib.file.File(self.trashdir, ensure="directory")
         self += batou.lib.file.File(
-            "/etc/local/nixos/trash.nix",
+            f"/etc/local/nixos/{self.file_name}",
             content=dedent(
                 """\
             {