Removed unnecessary record entries in function definitions.

Also, absolute positioning applied to make it look nicer.

It's quite ugly to display the buttons under the input box for rename, fixed to
have check/remove buttons on the right of the input.

Also, rename box "close" button added.

- some Tree.purs code cleanup (imports)
- file upload via drop onto tree node

Merge branch 'dev-search-field-styling' of ssh://gitlab.iscpif.fr:20022/gargantext/purescript-gargantext into dev-merge

Merge branch 'conference-presentation' of https://gitlab.iscpif.fr/gargantext/purescript-gargantext into conference-presentation

This reverts commit 095c1b53.

This reverts commit 65e9e0cd.