v2.11.0-rc.1 JSON:API release

Deployment notes:

• This release requires PHP version >= 7.2.5 (PHP 7.4 or later preferred)
• If you are upgrading from Zookeeper 2.10.x, run the script db/convert_v2_10_0_to_v2_11_0.sql
• See INSTALLATION.md for complete installation instructions. Important: If you are upgrading, please read in particular the new section Install Composer dependencies.

NEW this release:

• migrated all third-party dependencies to Composer (#249)
• added new JSON:API (#258, #253, #256)
• added APIKEY authentication (#255)
• deprecated legacy API (#261)

Issues resolved this release:

• fixed RewriteRule error under fastcgi (#252)
• updated to suppress home page push functionality when disabled (#250)
• fixed special character display in Library Editor (#259)

The release also includes a roll-up of the following hotfixes:

• fixed timestamping for shows which commence at midnight (#251)
• fixed timestamp display (#239)