Don't keep the default tile data blocked from swapping

Summary:
We don't access the raw data of it usually. And is cases we do
we should block it separately.

This patch is needed to be able to migrate the leftover of tiles
to the new pool when a document is closed.

Release all the tile pools forcefully when a document is closed

This approach is a bit hackish, but it is the best thing we can do.
When the document is closed and the pool still contains a few tiles,
we artificially "swap-out" the tiles into a QList, purge the data in
the tile data pools and "swap-in" the tiles back.

Surely, we will not get an ACM award for this solution, but at least it
works ;)

CCBUG:364848

Implement data pool for the chunks in openGL canvas updates

This patch implements KisTextureTileInfoPool. A special object that keeps
track of all the chunks allocated during the openGL canvas updates.

This class is also capable of tracking multiple openGL tile sizes
and color space pixel sizes.

It should fix the most of the memory fragmentation problems,
especially on Windows.

CCBUG:363334,364848

Fix warning

Merge remote-tracking branch 'origin/master' into kazakov/memory-optimizations

Test Plan: Open any **huge image** in Krita and try to work with it, Krita should not consume more memory with time. The RAM shouldn't also grow with reopening the same large image multiple times. Well, it will grow anyway, but not much.

Reviewers: rempt

Subscribers: dkazakov

Differential Revision: https://phabricator.kde.org/D2236