Add instructions for testing and deploying xblocks in the LMS
Add instructions for testing and deploying xblocks in the LMS

[LMS-2059]
[LMS-2060]
[LMS-1216]

nagyistoce/edx-XBlock,lovehhf/XBlock,lovehhf/xblock-sdk,edx-solutions/XBlock,edx/xblock-sdk,lovehhf/XBlock,stvstnfrd/xblock-sdk,nagyistoce/edx-xblock-sdk,open-craft/XBlock,open-craft/XBlock,edx/xblock-sdk,lovehhf/xblock-sdk,mitodl/XBlock,dcadams/xblock-sdk,edx-solutions/xblock-sdk,edx-solutions/xblock-sdk,edx-solutions/xblock-sdk,edx/XBlock,4eek/XBlock,nagyistoce/edx-xblock-sdk,Lyla-Fischer/xblock-sdk,Pilou81715/hackathon_edX,Lyla-Fischer/xblock-sdk,nagyistoce/edx-XBlock,EDUlib/XBlock,mitodl/XBlock,jamiefolsom/xblock-sdk,dcadams/xblock-sdk,jamiefolsom/xblock-sdk,jamiefolsom/xblock-sdk,nagyistoce/edx-xblock-sdk,lovehhf/xblock-sdk,nagyistoce/edx-xblock-sdk,dcadams/xblock-sdk,edx-solutions/xblock-sdk,Lyla-Fischer/xblock-sdk,Pilou81715/hackathon_edX,edx/xblock-sdk,stvstnfrd/xblock-sdk,Pilou81715/hackathon_edX,lovehhf/xblock-sdk,edx-solutions/XBlock,jamiefolsom/xblock-sdk,4eek/XBlock,EDUlib/XBlock,edx/XBlock,stvstnfrd/xblock-sdk,Pilou81715/hackathon_edX