refactor: introduce commons module

[ata-nas]

Problem

Generally every project has utility classes which are usually just full of static methods. Also, there are most likely "precondition" classes which are again full of static methods that aim to check for certain preconditions. Also, there are classes with constants that could be used in more than one place.

Since we have a few subprojects which are technically in different modules, we have no way (or at least not a good one) to reuse this logic. Some logic will be relevant in more than one place. There is no need to duplicate this logic. Also it makes little sense to depend on a subproject just to use it's utilities (and sometimes such dependencies might be impossible).

Solution

• create a new commons module;
• abstract all logic that could be reused (as described in Problem), based on classes above;
• refactor all places to facilitate the new logic;

Alternatives

N/A