Fix web warnings

[emilk]

Running our web viewer (e.g. with cargo r -p rerun --features web_viewer -- ../objectron.rrd --web-viewer) produces a lot of warnings in the console (mostly WebGL-related). For Firefox we get:

The script from “http://127.0.0.1:9090/re_viewer.js” was loaded even though its MIME type (“”) is not a valid JavaScript MIME type.
WEBGL_debug_renderer_info is deprecated in Firefox and will be removed. Please use RENDERER. [re_viewer.js:841:37](http://127.0.0.1:9090/re_viewer.js)
WebGL warning: getSyncParameter: ClientWaitSync must return TIMEOUT_EXPIRED until control has returned to the user agent's main loop. (only warns once)
WebGL warning: texSubImage: Tex image TEXTURE_2D level 0 is incurring lazy initialization.
WebGL warning: texSubImage: Texture has not been initialized prior to a partial upload, forcing the browser to clear it. This may be slow.
WebGL warning: texSubImage: Uploads from a buffer with a final row with a byte count smaller than the row stride can incur extra overhead.
WebGL warning: drawArraysInstanced: Drawing without vertex attrib 0 array enabled forces the browser to do expensive emulation work when running on desktop OpenGL platforms, for example on Mac. It is preferable to always draw with vertex attrib 0 array enabled, by using bindAttribLocation to bind some always-used attribute to location 0.

For the sake of log hygiene we should try to fix all of these.

[Wumpf]

getSyncParameter: has a tracking issue on wgpu here gfx-rs/wgpu#3064

WEBGL_debug_renderer_info: Related to gfx-rs/wgpu#3519