mod_storage_sql: Add UPSERT support Currently limited to SQLite3 for lack of testing on other databases. Adds a migration to replace the non-UNIQUE prosody_index, renaming it prosody_unique_index since ALTER INDEX does not seem to be portable.

module:log("error", "mod_pep_plus has been renamed to mod_pep, please update your config file. Auto-loading mod_pep...");
module:depends("pep");