Prepares for v3.0.3 machine release

[lucian151]

Improvements:

• Switches to M3 square nuts in 12 locations to improve the LumenPnP assembly process
• Updates the pump-mount design to support using m3-square-nut
• Rotates the tensioner-arm's M5 hex nut pocket on front-left-leg and front-right-leg to improve strength
• Introduces rubber-feet to the machine design
• Adds recesses to all legs to locate the rubber-feet properly
• Updates mobo-top-cover to improve legibility of the Boot and Reset text
• Updates mobo-top-cover to eliminate the tiny slots TMC2209 aux pin headers used to pass through
• Adds white PLA to BOM to reduce usage of PETG

Bug Fixes:

• Updates fastener counts after performing an audit