Leave only one json library in deps (jsonista or data.json)

[soulflyer]

First check which of the 2 json decoding libraries is the best to use. Feeling is that jsonista is the best choice but confirm this before proceeding.
https://www.juxt.pro/blog/json-in-clojure

[a-luz]

This will be solved together with #220. When I finish removing lein from the project I'll remove one of those two libraries

[soulflyer]

Both are still present, but jsonista is not there in the deps.edn file.
We should attempt to remove data.json as it is only used for simple read and write calls in xiana/db.clj
(There are other occurrences in the examples)
jsonista should be added to deps.edn and data.json removed.