The "subdomain" label is redundant, to the extent it's even
accurate -- this is really just the URL we want to display,
which may or may not involve a subdomain. Similarly "external".
The former `external_api_path_subdomain` was never a path -- it's a
host, followed by a path, which together form a scheme-relative URL.
I'm not quite convinced that value is actually the right thing in
2 of the 3 places we use it, but fixing that can start by giving an
accurate name to the thing we have.
This commit migrates all webhooks to use check_send_stream_message
instead of check_send_message. The only two webhooks that still
use check_send_message are our yo and teamcity webhooks. They
both use check_send_message for private messages.
All webhook fixtures in zerver/fixtures/<webhook_name> have now
been moved to dedicated webhook-specific directories under
zerver/webhooks/<webhook_name>/fixtures, where <webhook_name> is
the name of the webhook.
neiljp (Neil Pilgrim)
rht
Eeshan Garg
Greg Price
Robert Hönig
Jack Zhang
Raghav Jajodia
Tomasz Kolek