[MIRROR] Renames vars on pdas and removes ntnet_relays glob [MDB IGNORE] (#24960)

* Renames vars on pdas and removes ntnet_relays glob (#79595)

## About The Pull Request

- replaces the ntnet_relays global list with ``get_machines_by_type``
- renames ``transfer_access`` var on PDA to ``download_access`` &
``required_access`` to ``run_access`` to better describe what they do,
because on more than one ocassion I've confused myself with the two
terms and ended up doing something unintentional (see:
https://github.com/tgstation/tgstation/pull/74269)

## Why It's Good For The Game

Kills a useless global list and makes pda code a little less confusing.

## Changelog

Nothing player-facing.

* Renames vars on pdas and removes ntnet_relays glob

---------

Co-authored-by: John Willard <53777086+JohnFulpWillard@users.noreply.github.com>

code/modules/modular_computers/file_system/programs/radar.dm

@@ -220,7 +220,7 @@
 	filedesc = "Lifeline"
 	extended_desc = "This program allows for tracking of crew members via their suit sensors."
 	requires_ntnet = TRUE
-	transfer_access = list(ACCESS_MEDICAL)
+	download_access = list(ACCESS_MEDICAL)
 	available_on_ntnet = TRUE
 	program_icon = "heartbeat"
 
@@ -260,7 +260,7 @@
 	filedesc = "Custodial Locator"
 	extended_desc = "This program allows for tracking of custodial equipment."
 	requires_ntnet = TRUE
-	transfer_access = list(ACCESS_JANITOR)
+	download_access = list(ACCESS_JANITOR)
 	available_on_ntnet = TRUE
 	program_icon = "broom"
 	size = 2