Add Guide on Repairing the Robot

[ysims]

We have the start of a hardware repair guide in #67 but we need to

• Flesh out the page more
• Get renders of the robot's parts to better show the process.

@Bidski has a good layout in the PR comments:

General guide:

• How to repair a servo
• How to remove the NUC
• How to install the NUC
• How to detach the arm from the shoulder
• How to detach the shoulder from the torso
• How to attach the arm to the shoulder
• How to attach the shoulder to the torso

A specific repair guide, this example is 'repairing the shoulder pitch servo':

• Detach arm from shoulder
• Detach shoulder from torso
• Remove NUC
• Remove shoulder pitch servo
• Repair/replace shoulder pitch servo
• Install shoulder pitch servo
• Install NUC
• Attach shoulder to torso
• Attach arm to shoulder
• Test

This should be introduced in multiple PRs. A possible approach to splitting it up:

• Add in skeleton of the page with each section we want to fill in (not filled in yet)
• A different PR for each section - ie one PR for 'How to repair a servo', one PR for 'How to remove the NUC, one PR for 'How to repair the shoulder pitch servo', etc