suit: remove duplicate CoAP code

[bergzand]

Description

From sys/include/suit/coap.h:

/*                                                                               
 * Dear Reviewer,                                                                
 *                                                                               
 * At the time of PR'ing this code, there was a pile of CoAP PR's waiting for    
 * reviews.  Some of that functionality is needed in one way or another for      
 * SUIT. In order to not block software updates with CoAP refactoring, some of   
 * the work-in-progress code has been copied here.  We expect this to be         
 * removed as soon as CoAP in master provides similar functionality.             
 *                                                                               
 * As this is internal code that will go soon, I exclude this from Doxygen.      
 *                                                                               
 * Kaspar (July 2019)                                                            
 */                                                                              

@kaspar I think it is time we start to clean this code up 😉.

• CoAP subtree handling (refactor to prefix handling sys/net/application_layer/nanocoap: Add path prefix option #11098)
• CoAP blockwise request callback
• CoAP blocksize defines

Useful links

None

[aabadie]

@bergzand any plan soon to address the 2 remaining points ? ;)

[stale]

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[miri64]

I guess this is still an issue, right?

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. If you want me to ignore this issue, please mark it with the "State: don't stale" label. Thank you for your contributions.

[miri64]

• CoAP blockwise request callback

this was solved recently, right?