Revert MongoDB credentials removal

This MR reverts the changes in !22 (merged)

It turns out that the problem was in the infrastructure and now everything is working as expected with credentials passed as ENV variables.

@valerii.kalashnikov @lyuben.penkovski

added Need review label

requested review from @tziai

assigned to @yordan.kinkov

approved this merge request

@yordan.kinkov approved

Will it work with the current compose DB config - URL contains user/pass and USER/PASS are also set as ENV variables?

resolved all threads

LGTM

mentioned in commit 4dfe4ef4

merged