move default modules from /modules/default to /defaultmodules (#4019)

Since the project's inception, I've missed a clear separation between
default and third-party modules.

This increases complexity within the project (exclude `modules`, but not
`modules/default`), but the mixed use is particularly problematic in
Docker setups.

Therefore, with this pull request, I'm moving the default modules to a
different directory.

~~I've chosen `default/modules`, but I'm not bothered about it;
`defaultmodules` or something similar would work just as well.~~

Changed to `defaultmodules`.

Let me know if there's a majority in favor of this change.

Author: khassel

.gitignore

@@ -54,9 +54,8 @@ Temporary Items
 .directory
 .Trash-*
 
-# Ignore all modules except the default modules.
+# Ignore all modules
 /modules/*
-!/modules/default
 
 # Ignore changes to the custom css files but keep the sample and main.
 /css/*

cspell.config.json

@@ -343,11 +343,11 @@
 	"ignorePaths": [
 		"css/roboto.css",
 		"node_modules/**",
-		"modules/!(default)/**",
-		"modules/default/**/translations/!(en).json",
-		"modules/default/calendar/windowsZones.json",
-		"modules/default/clock/faces/*.svg",
-		"modules/default/weather/providers/yr.js",
+		"modules/**",
+		"defaultmodules/**/translations/!(en).json",
+		"defaultmodules/calendar/windowsZones.json",
+		"defaultmodules/clock/faces/*.svg",
+		"defaultmodules/weather/providers/yr.js",
 		"tests/mocks/**",
 		"tests/e2e/modules/clock_es_spec.js",
 		"translations/**"