Update Developer Documentation Common Issues

[gljivar]

Update Developer Documentation page with following notes:

• Current setup works with Node 10.15

In case following is encountered:

leveldown@3.0.0 install /home/miroslav/Projects/powerplant/node_modules/leveldown
prebuild-install || node-gyp rebuild
It might be needed to install:

• Python 2.7
• Make
• g++
• node-gyp

[petteripitkanen]

Since the move from MongoDB to PouchDB, powerplant might also work with older Node.js releases. This could be tested before the documentation is updated.