Allow Slack Team Name in room name

[peakematt]

This allows including the Slack server name in the name of Matrix rooms created for bridged channels.

This is helpful if a user has multiple Slack servers bridged. Each server is probably going to have a "#General" channel. This helps in differentiating them.

Then, config could look something like:

bridge:
    # Localpart template of MXIDs for Slack users.
    # {{.}} is replaced with the internal ID of the Slack user.
    username_template: slack_{{.}}
    # Displayname template for Slack users.
    # TODO: document variables
    displayname_template: '{{.RealName}} (S)'
    bot_displayname_template: '{{.Name}} (bot)'
    channel_name_template: '#{{.Name}} ({{.TeamName}})'
    portal_message_buffer: 128
    # Should the bridge send a read receipt from the bridge bot when a message has been sent to Slack?
    delivery_receipts: true

[crazychatting]

I am so looking forward for this!

[peakematt]

PR #13 replaces this. Closing.