Update b&w logos on brand page

[sskylar]

• [x] Remove old b&w wordmark options:

• [x] Replace with these options (drive):

• [x] Add note to use m workmark in cases where only 1 color is possible (e.g. screenprinting, faxes, etc)

[danielgamage]

looks done via mastodon/joinmastodon/pull/217