[alias-server] Initialize serverState database collection with read and write helper methods

Summary:
T3060

Depends on D13701

Initialize serverState collection with read and write helper methods.

serverState will be used to determine how many tx from chronik tx history call have not yet been processed by the server.

Test Plan: npm test

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Subscribers: Fabien

Differential Revision: https://reviews.bitcoinabc.org/D13702