Fix #7685: Doc image links (#7698)

* Fix image link in custom-script.md

* Fix image link in cable.md

* Fix image link in power.md

docs/core-functionality/power.md

@@ -5,4 +5,4 @@
 
 # Example Power Topology
 
-![Power distribution model](/media/power_distribution.png)
+![Power distribution model](../media/power_distribution.png)

docs/customization/custom-scripts.md

@@ -240,7 +240,7 @@ An IPv4 or IPv6 network with a mask. Returns a `netaddr.IPNetwork` object. Two a
 !!! note
     To run a custom script, a user must be assigned the `extras.run_script` permission. This is achieved by assigning the user (or group) a permission on the Script object and specifying the `run` action in the admin UI as shown below.
 
-    ![Adding the run action to a permission](/media/admin_ui_run_permission.png)
+    ![Adding the run action to a permission](../media/admin_ui_run_permission.png)
 
 ### Via the Web UI
 

docs/models/dcim/cable.md

@@ -25,7 +25,7 @@ A cable may be traced from either of its endpoints by clicking the "trace" butto
 
 In the example below, three individual cables comprise a path between devices A and D:
 
-![Cable path](/media/models/dcim_cable_trace.png)
+![Cable path](../media/models/dcim_cable_trace.png)
 
 Traced from Interface 1 on Device A, NetBox will show the following path: