doppler: add page (#13345)

Co-authored-by: Sebastiaan Speck <12570668+sebastiaanspeck@users.noreply.github.com>
Co-authored-by: spageektti <git@spageektti.cc>

pages/common/doppler-secrets.md

@@ -0,0 +1,24 @@
+# doppler secrets
+
+> Manage your Doppler project's secrets.
+> More information: <https://docs.doppler.com/docs/accessing-secrets>.
+
+- Get all secrets:
+
+`doppler secrets`
+
+- Get value(s) of one or more secrets:
+
+`doppler secrets get {{secrets}}`
+
+- Upload a secrets file:
+
+`doppler secrets upload {{path/to/file.env}}`
+
+- Delete value(s) of one or more secrets:
+
+`doppler secrets delete {{secrets}}`
+
+- Download secrets as `.env`:
+
+`doppler secrets download --format=env --no-file > {{path/to/.env}}`