feat: renamed config options with prefixes; added aliases for old names

* secret-is-base64 -> jwt-secret-is-base64
* role-claim-key -> jwt-role-claim-key
* max-rows -> db-max-rows
* pre-request -> db-pre-request
* root-spec -> db-root-spec
* db-schema -> db-schemas

This is not a breaking change, because aliases are added as well.

refactor: sorted all config keys alphabetically where applicable

test/io-tests/configs/unix-socket.config

@@ -1,5 +1,5 @@
 db-uri = "$(POSTGREST_TEST_CONNECTION)"
-db-schema = "test"
+db-schemas = "test"
 db-anon-role = "postgrest_test_anonymous"
 db-pool = 1
 server-host = "127.0.0.1"