Add support to code timestamp
The Art developers requires to have a code timestamp to group their nightly builds that test the same code but with different configurations.
In the DB structure we will add a new optional attribute named "codetimestamp".
This attribute will contain a full timestamp with date and time, but for now we will use only the date part.
The value for this attribute is known when the CI build starts, and its value will be assigned when the CI build is initialized through the "build/add" command.
The information about the "codetimestamp" will be shown in the CI web app as part of the "Build" column, under the experiment, in the form [YYY-MM-DD].
As this attribute is optional, it will show up only if it is used by the specific instance of the CI web app.
This attribute will be searchable, to allow the users to filter builds by 'codetimestamp'.