Allow writing to all of pinaxcon/site_media/media

We previously allowed writing to the `documents` sub-directory, but we also need
to write to `speaker_photos` to upload speaker photos. Simplest to allow writing
to the `media` parent directory.

Avoid showing the test@example.com email address on the password reset page

Also updated login form to prompt you to use your username if you fail to login
with what looks like an email address.

Improve button wording on speaker management page

"Cancel" implied that the button would revert changes you'd made to add
speakers.

Set logging level to INFO and xmlschema logging to WARNING

This eliminates the noisy messages about XML namespaces on startup and during
management commands.

Add a copy of 500.html that matches our template blocks

The builtin `pinax_theme_bootstrap` uses `body` instead of `content`.

Make vendored symposion into an installable Python package

This allows us to install with `pip install "-e vendor/symposion"` similar to
the other vendored packages. There's no good reason for this to be different to
the others and depend on PYTHONPATH hacking.

Re-add

Switch vendored requirements to "editable" to simplify development

This will allow us to remove the `sys.path` hacking in pinaxcon/settings.py.

Remove speaker photo for now

Causing errors that we don't have time to debug.

Remove use of directory under /run

Seems to get remove after reboot.

Allow primary topic to be null

We hide this field.

Add additional account app templates

This works around use block "body" when we need block "content".

Switch default country to US, currency to USD, tax to zero

Also default linux_australia to field to false to avoid IntegrityError.

Update checkin details

Add flags for sections on the checkin page so they can be switched
on and off as required.
Display the number of raffle tickets purchased by the attendees.

Update checking camera switcher

Fix camera selection using correct ID value.
Adjust column layout for mobile devices.

Add camera selector to checkin page

Allow the camera to be selected so tablets can use the
rear camera as well as the front camera.

Update checkin page

Display penguin dinner tickets.
Hide Venueless information panel.

Update attendee profile

Remove reference to Open Hardware kit as this is not happening in 2023.
Set lca_announce field to default of False given field is hidden.