(REF, release#17) Move list of core-exts to separate file

distmaker/core-ext.txt

+## This is a list of core-extensions stored in the 'ext' folder. These should be included in release
+## workflows, e.g. flagging new versions and building tarballs.
+
+## Note: This file should only be consumed internally (by release/distribution tools).
+## Future versions may change or obsolete the file without notice.
+
+afform
+authx
+contributioncancelactions
+eventcart
+ewaysingle
+financialacls
+flexmailer
+greenwich
+oauth-client
+payflowpro
+recaptcha
+search_kit
+sequentialcreditnotes

distmaker/dists/common.sh

@@ -118,19 +118,8 @@ function dm_install_coreext() {
 ## Get a list of default/core extension directories (space-delimited)
 ## reldirs=$(dm_core_exts)
 function dm_core_exts() {
-  echo ext/search_kit
-  echo ext/sequentialcreditnotes
-  echo ext/flexmailer
-  echo ext/eventcart
-  echo ext/ewaysingle
-  echo ext/financialacls
-  echo ext/afform
-  echo ext/authx
-  echo ext/greenwich
-  echo ext/contributioncancelactions
-  echo ext/payflowpro
-  echo ext/oauth-client
-  echo ext/recaptcha
+  ## grep to exclude comments and blank lines
+  grep '^[a-zA-Z]' "$DM_SOURCEDIR"/distmaker/core-ext.txt
 }
 
 ## Copy all packages