[BE] Add new field LastVisit field in https://brainup.fun/admin/users response

[ElenaSpb]

[BE] AddLast visit field in https://brainup.fun/admin/users response that will be about last visit to our site.
not about last done exercises as it is now. current value from Last Visit move to field Last study activity

[chackomathew]

@ElenaSpb I'm planning to capture the Last visit in FirebaseTokenAuthenticationFilter.kt after authentication. So the last visit is updated each time request for a user is received.

Do you see any issues with this approach or another better solution?

[naXa777]

May I continue from where @chackomathew left off and complete the task?

[lifeart]

Hi @naXa777 sure, go on!

[naXa777]

I opened new PR #2527 with a solution (back-end part). Please review.

I don't understand this part of the task:

not about last done exercises as it is now. current value from Last Visit move to field Last study activity

There was no Last Visit field before, or maybe it was removed recently, IDK. @ElenaSpb, please clarify.