Bazaar - Add back end to bazaar's mainpage

[azackmatoff]

Add back end to #1190

[clangenb]

Not everything is possible yet. We can:

• Get all businesses of a community
• Get all offerings of a community

We can't get: all oferings of a business: encointer/pallets#318

[clangenb]

I have updated the gesell rpc node, which now returns the following:

curl http://gesell.encointer.org:9933 -H "Content-Type:application/json;charset=utf-8" -d '{ "jsonrpc":"2.0", "id":1, "method":"encointer_bazaarGetBusinesses", "params": [{ "geohash": "0x7530716a39", "digest": "0x8fa5e673" }] }'

{"jsonrpc":"2.0","result":[{"controller":"5EXDFzxPembiCPqcxHkmXHjcGEf2FvL6QK22yNs2QxFiDKgS","businessData":{"url":"QmTTHFZ7roMRZD619Tn8mAttAmn2CnAh8NUXR4VocRvcfh","lastOid":1}},{"controller":"5GrwvaEF5zXb26Fz9rcQpDWS57CtERHpNehXCPcNoHGKutQY","businessData":{"url":"QmWYjfdsScf2mBxKgGbBq822FzRNkB5nG6wjK2NKLw1Ewz","lastOid":2}}],"id":1}%

[clangenb]

Closed by #1265