mutt: Update neomutt configuration

Changed some colors, some keymaps and made it more flexible for new mail
account setups. Also removed most of the static gmail-related account
stuff since I don't need this in my public repo.

office/.config/neomutt/account

@@ -2,15 +2,14 @@
 # local maildir settings
 set mbox_type = Maildir
 set folder    = ~/documents/mail # This has the shortcut '+' or '='
-set spoolfile = "+inbox"         # This has the shortcut '!'
-set postponed = "+drafts"
-set trash     = "+trash"
-# Disable saving outgoing mail since Gmail saves them by default.
-unset record
+set spoolfile = "+Inbox"         # This has the shortcut '!'
+set postponed = "+Drafts"
+set record    = "+Sent"
+set trash     = "+Trash"
 mailboxes   ! \
-            "+important" \
-            "+sent" \
-            "+drafts" \
-            "+trash" \
-            "+archive"
+            "+Sent" \
+            "+Drafts" \
+            "+Trash" \
+            "+Archive" \
+            "+Junk"