New TurnKey Drupal 7 version (18.1)

v18.1 rebuild - includes latest Debian & TurnKey packages.
Update Drupal 7 to lastest v7.101.
Ensure hashfile includes URL to public key - closes #1864.
Configuration console (confconsole) - v2.1.6:
- Bugfix broken DNS-01 Let's Encrypt challenge - closes #1876 & #1895. Fixed in v2.1.5 - already included in some appliances.
- Let's Encrypt/Dehydrated - bugfix cron failure - closes #1962.
- General dehydrated-wrapper code cleanup - now passes shellcheck.
Web management console (webmin):
- Include webmin-logviewer module by default - closes #1866.
- Upgraded webmin to v2.105.
- Replace webmin-shell with webmin-xterm module by default - closes #1904.
Reduce log noise by creating ntpsec log dir - closes #1952.
Apache mod_evasive config improvements:
- Bump DOSPageCount from (default) 2 -> 5 - closes #1951.
- DOSLogDir - use default log dir & fix permissions - closes #1950.
- Add DOSWhitelist example - commented out.
Include new 'tkl-update-php' script - to make updating/changing PHP version easier for end users. [Marcos Méndez @ POPSOLUTIONS
DEV: Add support for setting max_execution_time & max_input_vars in php.ini via appliance Makefile (PHP_MAX_EXECUTION_TIME & PHP_MAX_INPUT_VARS).