Set larger limit on file uploads

[MatthewHager]

Right now the PHP limit is set to 2MB which keeps us from being able to upload larger images. Let's set the PHP limit to 25MB and then the site builder can set this lower.

[ergonlogic]

I'm not so sure this is such a good idea, as least, as a default. This could lead to nasty surprises if a dev tests and deploys a site to a server where they don't have control over php.ini.

Perhaps integrating something upstream, along the lines of https://www.drupal.org/project/hosting_variables, could resolves this in a more portable fashion.