Merge branch 'asset-engine' into asset-experiments

Conflicts:
source/blender/blenloader/intern/readfile.c

Changed most of ID_IS_LINKED_foo checks as needed.

Basically, due to new 'virtual' libraries & 'path' assets, we consider those 'virtualmy linked' IDs as:
* Local for editing purpose (i.e. they are editable).
* Linked for datablock management purposes (i.e. they can be made local, etc.).

Note: all this is more like a quick hack to test 'file-based' asset repositories (like cloud)
in comming weeks. I really do not think we should use that in the end, an full-featured
'overriding ID' system (as proposed in replacement of proxies for 2.8) would be much saner imho.

Merge branch 'master' into asset-engine

Merge branch 'master' into asset-engine

Merge branch 'master' into asset-engine

Conflicts:
source/blender/windowmanager/intern/wm_files_link.c

Some more small fixes regarding ID/library asset handling.

Add more macros to differentiate actual linked datablocks from 'virtually' linked ones (assets only).

Not yet used in code.

Merge branch 'master' into asset-engine

Conflicts:
source/blender/windowmanager/intern/wm_init_exit.c

Merge branch 'master' into asset-experiments

Conflicts:
source/blender/blenloader/intern/readfile.c
source/blender/windowmanager/intern/wm_init_exit.c

Merge branch 'master' into asset-engine

Conflicts:
source/blender/blenloader/intern/readfile.c

Merge branch 'master' into asset-engine

Fix memleak whene deleting IDs with uuid!

Add utility to print UUID (could make it nicer, but for now will do).

Reduce re-allocation while fetching UUIDs per asset engine (asset reload area).

Split Library/ID asset-related management into own library_asset file.

This is specific enough to deserve its own file imho, and though rather small
currently, it's likely to grow...

Cleanup: rename BKE_asset to BKE_asset_engine.

Since this file mostly defines/handles interactions with asset engines...

Asset handling itself is more done in library area (will split it too in next commit).

Merge branch 'master' into asset-engine

Merge branch 'master' into asset-engine

Conflicts:
source/blender/blenloader/intern/writefile.c

Merge branch 'master' into asset-experiments

Merge branch 'master' into asset-experiments

Conflicts:
source/blender/blenkernel/BKE_library.h
source/blender/blenkernel/intern/brush.c
source/blender/blenkernel/intern/library.c
source/blender/blenkernel/intern/library_remap.c
source/blender/blenkernel/intern/mesh.c
source/blender/blenloader/BLO_readfile.h
source/blender/blenloader/intern/readfile.c
source/blender/blenloader/intern/writefile.c
source/blender/editors/space_action/space_action.c
source/blender/editors/space_clip/space_clip.c
source/blender/editors/space_file/filelist.c
source/blender/editors/space_graph/space_graph.c
source/blender/editors/space_image/space_image.c
source/blender/editors/space_logic/space_logic.c
source/blender/editors/space_nla/space_nla.c
source/blender/editors/space_node/space_node.c
source/blender/editors/space_outliner/outliner_edit.c
source/blender/editors/space_sequencer/space_sequencer.c
source/blender/editors/space_text/space_text.c
source/blender/editors/space_view3d/space_view3d.c
source/blender/makesrna/intern/rna_ID.c
source/blender/makesrna/intern/rna_main_api.c
source/blender/windowmanager/intern/wm_files_link.c
source/blender/windowmanager/wm_files.h