Rework the thumbnailer

[urvashi-7span]

In this PR,

• New thumbnail flow as discussed in Dynamic default action and quality for thumbnail information #813
• As discussed with @bjgajjar, added migrations in upgrades folder

@benhaynes @rijkvanzanten
Let me know the list of options that are supported for thumbnail creation so I will do code according to that.

Resolves #813

[rijkvanzanten]

• Lets rename hash_id to private_hash
• directus_files.id primary key should be used to name all files in the filesystem (both original / thumbnails)
• directus_files.filename holds the original name of the file from when it was uploaded
• directus_files.id needs to be converted to a random hash, not an auto increment ID
• directus_files.private_hash should be randomly generated as well (does not have to be connected to id in any way)
• Both directus_files.id and directus_files.private_hash should be a 16-character alpha-numeric (A-Za-z0-9) string (make sure to use VARCHAR(16) as well)
• Get rid of file naming option in directus_settings
• Remove the other deprecated fields from directus_settings
• The key should work as a shorthand for the other values. Passing /assets/:hash?key=test should return the file according to the test setting instead of return "width: This value should not be blank. etc"
• thumbnail_whitelist_enabled should be on by default
• "The params doesn't don't match with the Thumbnail Whitelist."

Other than these points, this is really coming together! 😄 Happy to have this cleaned up a bit.

@urvashithakar @bjgajjar Did we ever find a solution / have any ideas about streaming the files instead of reading them in memory before sending them out?

[philleepflorence]

Will this PR allow the Admin to select the default thumbnail size and quality in directus_settings?
Currently, V8-RC2 is generating the thumbnail from the first size in directus_settings.thumbnail_dimensions, and using good as the quality.

Or will it generate all the thumbnail sizes that are listed?

[rijkvanzanten]

There's a split between system thumbnails that can't be changed, and a user-provided whitelist that can be used to add any dedicated sizes you want

[philleepflorence]

Okay, thanks!
I will await the next update to see if it changes the current behavior.

Currently with these sizes:
200x200,320x320,480x480,640x640,960x960,1280x1280,1600x1600,1900x1900
When you hit the files endpoint, it generates an array of 8 thumbnail rows but with the quality of good and action crop.
My hope is:

1. We can change the quality and action.
2. Choose the default thumbnail size or turn off the additional thumbnail rows.

Also if for some reason the list is as follows:
1280x1280,1600x1600,1900x1900,200x200,320x320,480x480,640x640,960x960
The thumbnail generated is 1280x1280.

[rijkvanzanten]

This is exactly what's possible now 🙂

Instead of setting what sizes are available, you're required to set what formats are allowed, based on an array of objects containing

(key)
width
height
quality
fit

[philleepflorence]

Okay, so this is the way it is designed?

Also if for some reason the list is as follows:
thumbnail_dimensions: 1280x1280,1600x1600,1900x1900,200x200,320x320,480x480,640x640,960x960
The thumbnail generated in uploads is 1280x1280.

And querying the files endpoint returns an array of thumbnails for each of the sizes in thumbnail_dimensions for each file?