Configuring plugin options via INI file

[arthurian]

Hello,

We have a need to seed the plugin with configuration options prior to the plugin actually being installed. One way to do that is to run a bunch of database queries to insert the relevant key/value pairs into the options table. However, this PR provides an alternative by allowing site admins to configure the plugin options in options.ini ahead of time. When the plugin is installed, those options are picked up and override the existing defaults.

As its name implies, the options.ini file is completely optional, so if the file does not exist, the default options will be generated by the plugin as per usual and existing plugin clients will not be impacted by the change.

Any thoughts @dicksonlaw583? We intend to use this functionality in our ansible playbooks to pre-seed the options on a per-site basis since we have a bunch of sites we're managing that will use this plugin.

P.S. This is a fantastic plugin, so thank you for all your work on this!

[arthurian]

@dicksonlaw583 We're still actively using IiifItems in our multi-site Omeka deployment and just wanted to follow-up on this PR. Anything that would prevent this from being merged?

[dicksonlaw583]

My apologies for the delay in answering this PR. There is a new use case for Docker Compose where this feature will be useful, and so I will accept this PR. The corresponding documentation will be added shortly.

Thank you for your contribution to the plugin.