Add action message type

[JRoy]

Adds a message type which will show when a player runs the /action (/me) command.

Message Type:

# Configure which Discord channels different messages will be sent to.
# You can either use the names of the channels listed above or just the id of a channel.
# If an invalid channel is used, the primary channel will be used instead.
#
# To disable a message from showing, use 'none' as the channel name.
message-types:
  ...
  # Action messages sent when a player runs the /me or /action commands.
  action: primary

Message Format:

# The following entries allow you to customize the formatting of messages sent by the plugin.
# Each message has a description of how it is used along with placeholders that can be used.
messages:
  ...
  # This is the message sent to Discord when a player runs the /me or /action command.
  # The following placeholders can be used here:
  # - {username}: The name of the user who ran the command
  # - {displayname}: The display name of the user who ran the command
  # - {action}: The action (message) the user used in the command.
  # ... PlaceholderAPI placeholders are also supported here too!
  action: ":person_biking: {displayname} *{action}*"