feat(wm): padding for named workspaces

workspace-padding and container-padding take the index of a workspace's monitor
and its own index, so a script that names its workspaces still has to count them
to pad one, while focus-named-workspace, named-workspace-layout and
named-workspace-tiling already take the name.

named-workspace-padding and named-workspace-container-padding take the name
instead. They look the workspace up on every monitor the way the other named
commands do, set the same padding the commands by index set, and change nothing
for a name no workspace has.

The tests check the messages the subcommands send, that a named workspace takes
its paddings and the tile in front follows, and that a name nobody has changes
nothing. The commands sweep of the VM suite sends both commands to a real
session.

docs/cli/named-workspace-container-padding.md

@@ -0,0 +1,17 @@
+```text
+Set the container padding for the specified workspace
+
+Usage: named-workspace-container-padding <WORKSPACE> <SIZE>
+
+Arguments:
+  <WORKSPACE>
+          Target workspace name
+
+  <SIZE>
+          Pixels to pad with as an integer
+
+Options:
+  -h, --help
+          Print help
+
+```

docs/cli/named-workspace-padding.md

@@ -0,0 +1,17 @@
+```text
+Set the workspace padding for the specified workspace
+
+Usage: named-workspace-padding <WORKSPACE> <SIZE>
+
+Arguments:
+  <WORKSPACE>
+          Target workspace name
+
+  <SIZE>
+          Pixels to pad with as an integer
+
+Options:
+  -h, --help
+          Print help
+
+```