DIY module needs to be linked to Seeed

[Frijol]

Not available at the time of #34

Should be done as soon as we hear that Seeed has links online (@johnnyman727 is point of contact for this).

• get rid of the mixin 'module-left-unavailable'
• change GPS module back to 'module-left' mixin and add new shop link as the last argument
• manually relink the DIY module because it doesn't use a mixin