Construction Level Improvements (#5424)

Made some mapping changes to the construction level, namely for power and atmospherics, and gave it a unique area instead of having it connected to surface maintenance.

Feedback thread and screenshots: https://forums.aurorastation.org/viewtopic.php?f=18&t=12083

html/changelogs/furrycactus-constructionlevel.yml

@@ -0,0 +1,37 @@
+################################
+# Example Changelog File
+#
+# Note: This file, and files beginning with ".", and files that don't end in ".yml" will not be read. If you change this file, you will look really dumb.
+#
+# Your changelog will be merged with a master changelog. (New stuff added only, and only on the date entry for the day it was merged.)
+# When it is, any changes listed below will disappear.
+#
+# Valid Prefixes: 
+#   bugfix
+#   wip (For works in progress)
+#   tweak
+#   soundadd
+#   sounddel
+#   rscadd (general adding of nice things)
+#   rscdel (general deleting of nice things)
+#   imageadd
+#   imagedel
+#   maptweak
+#   spellcheck (typo fixes)
+#   experiment
+#   balance
+#################################
+
+# Your name.  
+author: Furrycactus
+
+# Optional: Remove this file after generating master changelog.  Useful for PR changelogs that won't get used again.
+delete-after: True
+
+# Any changes you've made.  See valid prefix list above.
+# INDENT WITH TWO SPACES.  NOT TABS.  SPACES.
+# SCREW THIS UP AND IT WON'T WORK.
+# Also, all entries are changed into a single [] after a master changelog generation. Just remove the brackets when you add new entries.
+# Please surround your changes in  double quotes ("), as certain characters otherwise screws up compiling. The quotes will not show up in the changelog.
+changes: 
+  - maptweak: "Improved the design of the construction level, adding atmospherics pipes and power cables to it from the cargo interstitial level airlock. Also gave it a new area designation, so it's not tied to the surface maintenance air and power alarm systems. Construction level and Cargo interstitial level airlocks made larger for the benefit of miners and engineers that need to move objects and machinery too."

maps/_common/areas/station/maintenance.dm

@@ -161,6 +161,18 @@
 /area/maintenance/storage
 	name = "Atmospherics"
 	icon_state = "green"
+	
+/area/maintenance/interstitial_main
+	name = "\improper Construction Level"
+	icon_state = "maintcentral"
+	
+/area/maintenance/interstitial_cargo
+	name = "\improper Cargo - Interstitial"
+	icon_state = "maint_cargo"
+	
+/area/maintenance/interstitial_bridge
+	name = "\improper Bridge - Interstitial"
+	icon_state = "maintcentral"
 
 // SUBSTATIONS (Subtype of maint, that should let them serve as shielded area during radstorm)