Allowing to suppress Embeds on MESSAGE_CREATE via. flags

[DManstrator]

Discord already supports suppressing embeds by setting the SUPPRESS_EMBEDS flag on the message. However setting flags is just possible on a MESSAGE_EDIT, not on MESSAGE_CREATE.

Due to that, the only way of suppressing embeds on MESSAGE_CREATE is currently to put all links into angle brackets (<link>).

Allowing this (and any other possible) flag to be set on MESSAGE_CREATE would be a nice QOL improvement, saving an additional request and preventing the generation of potential embeds in first place.

[freya022]

Additionally, some links cannot be put in between of <> since it would break Discord's URL parsing and take the right chevron as inside the URL

[muddyfish]

#3236

[DManstrator]

Was initially added with 95816a5 with an additional answer on #3236 (comment).

Thanks!