Finish implementing COBC file system

[PatrickKa]

Description

So far we only have basic file system commands like creating and deleting files and directories, or writing to and reading from files. What we actually need is functions to store programs that are to be sent to the EDU and results that come from the EDU. Of course, we also need to be able to delete them, check their integrity, etc. Since the file system is on the flash with which we communicate via SPI, we furthermore need to implement a fallback behavior for all those functions, in case the flash does not work.

To do

• Rename archive to (EDU) program #215
• Add functions to store EDU programs and results #216
• Add integrity check for EDU programs and results #217
• Add functions to remove EDU programs and results #218
• Add functions to read EDU programs and results #219
• Add functions to check available EDU programs and results #220

[PatrickKa]

Blocked by #186

[PatrickKa]

Blocked by #273