chore: simplify plugin readmes, changelogs and manifest descriptions

plugins/step-ca/CHANGELOG.md

@@ -2,15 +2,6 @@
 
 ## 1.0.0
 
-Bundled with Termix 2.9.0.
+First release, bundled with Termix 2.9.0.
 
-- Step CA sign-in moved out of core. The callback is now
-  `/plugin-api/step-ca/callback`; the 2.8 URI `/host/step-ca-callback`
-  still works and upgraded installs keep sending it until an admin turns
-  off "Use the old redirect URI".
-- The CA URL, fingerprint, provisioner and private endpoint list moved from
-  Admin Settings into this plugin's settings.
-- Issued certificates are stored encrypted in the plugin's own table, so
-  they survive a restart. Certificates cached by 2.8 are not carried over;
-  the next connection asks for one sign-in.
-- The terminal shows the sign-in dialog for Step CA hosts again.
+Adds the Step CA login type. Termix signs you in through a smallstep step-ca OIDC provisioner and gets a short-lived SSH certificate from the CA.