keychain: improve

- don't set pinentry manually, let local system manage it
- update cache-ttls to improve longevity

dot_local/share/private_gnupg/gpg-agent.conf

@@ -1,5 +1,5 @@
-default-cache-ttl 86400
-max-cache-ttl 86400
-pinentry-program /usr/bin/pinentry-qt
-allow-preset-passphrase
+default-cache-ttl 60480000
+default-cache-ttl-ssh 60480000
+max-cache-ttl 60480000
+max-cache-ttl-ssh 60480000
 enable-ssh-support