implement get books by search route

[wnbck]

• validation
• database query
• complete route + documentation

NOTE: see routes.md

[chawlapalak]

Hi @kwlskiy ,

I would like to work on this, please assign this to me. Thanks in advance!

[chawlapalak]

@kwlskiy The PR was submitted for this. Let me know if you need anything else or would like to merge them. Thanks