Upgrade PHP interpeter and code on turing to a modern, supported version.

[zymurgic]

There are problems with the current ancient PHP version on turing that is linked against OpenSSL 1.0, which can't connect to letsencrypt SSL sites.

1. Upgrade the flourish library code to a later version (though that framework seems to be abandonware itself, there have been upgrades in the past 8 years)
2. Identify any PHP constructs and quirks that only worked on PHP5, make any changes backwards-compatible.
3. Start using new PHP code
4. Find a new PHP package that will work on turing, or build from source, with all the extensions etc that are required.
5. Investigate upgrading turing to a more modern Debian. Having a nice good supported build of OpenSSL that the packages for that version of Debian supports would be good.

[zymurgic]

The lib/flourish (and even the last known release of libflourish) uses the old database access methods require PHP modules to be installed, and it handles the quirks of each DBMS internally, rather than using PDO. In our case, it's pgsql, and is built-in to PHP, rather than deprecated or moved to a PECL module.

[marksteward]

I literally wrote the Python bridge so we wouldn't have to do this.