browser (calls): add camera switching: - devices are listed on startup, and a `has_multiple_cameras` boolean is set - based on this data, switch camera button is hidden or not - a click/touch on the button will switch to the next available camera, and loop back to first one at the end

syntax: glob
.build
build
ctags_links/
dist/
.eggs/
env/
MANIFEST
.mypy_cache/
*.orig
*.pyc
*.pyo
.pytest_cache
*.pyv
Session.vim
stubs/
*.swo
*.swp
tags
tests/e2e/report*
_trial_temp/
twistd.log
twistd.pid
twisted/plugins/dropin.cache
*.un~
.vim
.vscode