Implement and document new Botserver setup routine.

Previously, the Botserver determined which bot to run for an
outgoing webhook by dispatching on a different URL endpoint
for each bot. Now, instead, the Botserver determines which bot
to run by the section header of the bot in the flaskbotrc.
This commit makes the frontend provide the new flaskbotrc
and updates the setup steps for the Botserver in the docs.

static/templates/settings/bot-settings.handlebars

@@ -71,7 +71,7 @@
                         <div class="input-group">
                             <label for="create_payload_url">{{t "Endpoint URL" }}</label>
                             <input type="text" name="payload_url" id="create_payload_url"
-                              maxlength=2083 placeholder="https://hostname.example.com/bots/followup" value="" />
+                              maxlength=2083 placeholder="https://hostname.example.com" value="" />
                             <div><label for="create_payload_url" generated="true" class="text-error"></label></div>
                         </div>
                         <div class="input-group">

templates/zerver/api/deploying-bots.md

@@ -43,13 +43,12 @@ pip install zulip_botserver
 1. Construct the URL for your bot, which will be of the form:
 
     ```
-    http://<hostname>:<port>/bots/<bot_name>
+    http://<hostname>:<port>
     ```
 
     where the `hostname` is the hostname you'll be running the bot
     server on, and `port` is the port for it (the recommended default
-    is `5002`).  `bot_name` is the name of the Python module for the
-    bot you'd like to run.
+    is `5002`).
 
 1. Register new bot users on the Zulip server's web interface.
 
@@ -59,9 +58,25 @@ pip install zulip_botserver
       the URL from above) and click on *Create bot*.
     * A new bot user should appear in the *Active bots* panel.
 
-1.  Download the `flaskbotrc` from the `your-bots` settings page. It
-    contains the configuration details for all the active outgoing
-    webhook bots. It's structure is very similar to that of zuliprc.
+1. Download the `flaskbotrc` from the `your-bots` settings page.
+
+1. Open the `flaskbotrc`. It should contain one or more sections that look like this:
+   ```
+   [foo]
+   email=foo-bot@hostname
+   key=dOHHlyqgpt5g0tVuVl6NHxDLlc9eFRX4
+   site=http://hostname
+   ```
+   Each section contains the configuration for an outgoing webhook bot. For each
+   bot, enter the name of the bot you want to run in the square brackets `[]`.
+   For example, if we want `foo-bot@hostname` to run the `helloworld` bot, our
+   new section would look like this:
+   ```
+   [helloworld]
+   email=foo-bot@hostname
+   key=dOHHlyqgpt5g0tVuVl6NHxDLlc9eFRX4
+   site=http://hostname
+   ```
 
 1.  Run the Zulip Botserver by passing the `flaskbotrc` to it. The
     command format is: