Add 'hash' configuration option for cache check method

[fredrikekelund]

It seems Grav supports a 'hash' cache check method, that looks at folder contents in their entirety, and generates an MD5 hash from the combined list of mtimes. See getgrav/grav@c718b8f for more details.

There should probably be an option in the admin panel for this 'hash' option.

[rhukster]

Fixed in Grav develop - getgrav/grav@e492fbd

[fredrikekelund]

@rhukster great! I like the fact that you added a bit more descriptive labels for the different options as well. Just a question, though – will the file cache check method really take media files into account? From looking at the source code for the Folder::lastModifiedFile method, it looks like it only takes .md and .yaml files into consideration?

[rhukster]

You are correct! I misremembered. Probably should of checked first :) Will fix

[rhukster]

You are correct, fixed.