ensures migration dir exists and writes state, up/down sql queries & info file to disk path string should look like this ".../migrations/dbname/2024-01-01T00_00_00".

returns: list of migrations, the active migration index (-1 if no active migration found) and "isInit" to check if the migrations directory was initialized.

primitive DbMigration type, only containing helper function, use migrationsLib for complete use a db migration directory will look like: /migrations/dbname/2024_01_01T00_00_00 this directory will contain files: "active" (present ONLY IF migration is currently active), "state.json" (a state snapshot of the CURRENT state) "up.sql" (sql file to go up to the next state) [COULD BE ABSENT IF LATEST STATE] "down.sql" (sql file to go down to the previous state) [ABSENT ON INIT MIGRATION] "info.md" (user maintained description of the current state changes relative to previous state) */.