* add admin akd key mongo implementations
* wire admin and key stores to mongo
* lint: wrong comment on keys store
* typos and comments corrections
* fix failed test on avatar resizer
* get rid of ineffectual assignment in test
* add tests for encoding fallback and mongo's keys & admin
* empty encode test adjusted
* add keyStore and switch all secret usage to this store
- implement static ks
- add shared secret
* lint: shadow in jwt and missing comment
* rename static key group to shared and use top-level shared secret
* move siteID extraction (from token) to internal func
* lint: merge var and assign for key test
Umputun
Anton KosourovandUmputun