Add 3D representations of infrastructures in glTF 2.0 format - #172

Move the lookup of the infrastructure to represent in database, with the error
raised when it is not found, from infrastructure drawer constructor to the
base Drawer class.

All representations of infrastructures, whatever their output format, start
with this lookup. Sharing it in base Drawer class lets upcoming 3D drawer of
infrastructures, and possibly other drawers in the future, reuse it with the
same behavior and error message as existing 2D drawers.

Assisted-by: Claude Opus 5.5

The selection of racks and rows to represent according to equipment_tags,
discard_empty_racks and other_racks drawing parameters was duplicated in the
draw() methods of infrastructure and axonometric infrastructure drawers, and
the check of equipment tags was duplicated in their methods drawing
equipment.

Move this logic into base Drawer class, in _select_infrastructure_racks(),
_part_contains_selected_equipment() and new _equipment_selected() methods,
used by both 2D infrastructure drawers.

Besides removing duplicated code, this ensures upcoming 3D drawer of
infrastructures, and any other future representation of infrastructures,
honours drawing parameters exactly as 2D drawers do, with a single place to
fix or extend this selection logic.

Assisted-by: Claude Opus 5.5

Move _rack_preceding_widths() method, which yields the widths of racks and
empty slots before a rack in its row, from room drawer to base Drawer class,
without modification.

This method defines how racks are positioned in their rows, including the
width assumed for empty slots. Any representation placing racks in rooms,
starting with upcoming 3D representation of infrastructures, must follow the
same rule to stay consistent with rooms diagrams. Sharing it in base Drawer
class avoids diverging implementations.

Assisted-by: Claude Opus 5.5

Move racks footprints overlap detection (polygons_overlap()) out of room
drawer module and equipment overlap detection (equipment_overlap()) out of
infrastructure drawer module, along with the detection of colliding equipment
in a list of racks extracted from infrastructure drawer as
colliding_equipment(), into new collisions module.

These functions are pure geometry, independent of any rendering. Gathering them
in a dedicated module lets upcoming 3D drawer of infrastructures, and future
drawers or other consumers of datacenters geometry, detect collisions exactly
as 2D drawers do without importing 2D drawers modules and their cairo
dependency.

Collisions warnings are now emitted by racksdb.drawers.collisions logger.

Assisted-by: Claude Opus 5.5

Add GltfInfrastructureDrawer to represent infrastructures in 3D, in glTF
JSON (gltf) and binary (glb) formats. The scene graph follows database
structure (room, racks row, rack, equipment) with metadata in node extras.
Rooms have textured raised floors with perforated tiles in front of racks
doors. Equipment tags filtering, ghosts, other racks, coloring rules and
collisions highlighting drawing parameters are honored.

Assisted-by: Claude Opus 5.5

Add shared drawer_class() factory to select drawer according to entity,
format and drawing parameters, used by both racksdb CLI and REST API.

Assisted-by: Claude Opus 5.5

Add gltf and glb drawing formats.

Assisted-by: Claude Opus 5.5

Cover glTF drawer, drawer class selection, CLI and REST API with gltf and
glb formats.

Assisted-by: Claude Opus 5.5

Add 2D/3D toggle in infrastructure details view. The 3D view loads the
infrastructure glb representation in an interactive three.js viewer,
loaded dynamically, with orbit controls, equipment highlighting and label
on hover, view reset and fullscreen mode.

Assisted-by: Claude Opus 5.5

Update infrastructure details page screenshot with 2D/3D toggle and add
screenshot of 3D view of infrastructure in fullscreen mode, with its shadowed
version. Add 3D view in overview diagrams, with screenshot embedded in SVG
optimized with scour.

Assisted-by: Claude Opus 5.5

Document gltf and glb formats of draw command, their restrictions to
infrastructures and incompatibility with coordinates, with an example.

Assisted-by: Claude Opus 5.5

Document 2D/3D toggle in infrastructure details page and the controls of the
interactive 3D view.

Assisted-by: Claude Opus 5.5

Mention 3D representations of infrastructures in glTF format in diagrams
section of overview page.

Assisted-by: Claude Opus 5.5

Assisted-by: Claude Opus 5.5