Sharing file browser

[RyRy79261]

closes #1043
closes #1157
closes #1162

[render]

Your Render PR Server URL is https://files-ui-stage-pr-1048.onrender.com.

Follow its progress at https://dashboard.render.com/static/srv-c2jnu9b2v8panf9vk5qg.

[Tbaut]

We said we'd put this on the side for the time being. Closing so as not to pollute our pulls list.

[Tbaut]

Oops I meant the other one sorry.

[render]

Your Render PR Server URL is https://files-ui-stage-pr-1048.onrender.com.

Follow its progress at https://dashboard.render.com/static/srv-c36bon85ou7u4hodod40.

[render]

Your Render PR Server URL is https://storage-ui-stage-pr-1048.onrender.com.

Follow its progress at https://dashboard.render.com/static/srv-c36boo05ou7u4hododkg.

[CLAassistant]

All committers have signed the CLA.

[lgtm-com]

This pull request introduces 3 alerts when merging 90586f1 into c5c925f - view on LGTM.com

new alerts:

• 3 for Unused variable, import, function or class

[lgtm-com]

This pull request introduces 3 alerts when merging e5d9c61 into c5c925f - view on LGTM.com

new alerts:

• 3 for Unused variable, import, function or class

[lgtm-com]

This pull request introduces 3 alerts when merging 6fad93e into c5c925f - view on LGTM.com

new alerts:

• 3 for Unused variable, import, function or class

[lgtm-com]

This pull request introduces 3 alerts when merging 6dec91e into c5c925f - view on LGTM.com

new alerts:

• 3 for Unused variable, import, function or class

[Tbaut]

This is working damn well! Went through the code quickly, left a couple comments there, and what I came across:

• Getting this in the console

Warning: Each child in a list should have a unique "key" prop.

Check the render method of `FileSystemTableItem`. See https://fb.me/react-warning-keys for more information.
    in span (at FileSystemTableItem.tsx:252)
    in FileSystemTableItem (at FileSystemItem.tsx:413)
    in FileSystemItem (at SharesList.tsx:905)

• When moving a file, the tree is not the right one (it's the one of not shared folders). (edit, made an issue out of it Move files inside shared browser isn't showing the right tree #1204)
• As discussed deleting a file should delete it altogether. (made an issue out of it Shared files and folder should be deleted directly and not go in the bin #1203)

[Tbaut]

Looking great, all is green, life is beautiful, thanks a lot for this huge one.
Created 2 small bug issues to tackle separately.

[FSM1]

Left 2 small comments, but looks great otherwise.

The SharesList component seems very much identical to the FilesList except for the menu options. We could potentially hoist the logic of getting these up to context, and just pass it in to the FilesList to avoid having the rest of that repeated.