NXCALS-851 Improved QueryBuilder API

• Easy way of date specification in text format
• More ways of specifying the start/end time (like start + period, etc)
• Have a specific api for one timestamp only like atDate(timestamp)
• Have a way to return the DataFrame directly from our builders (this is to be excluded to another task for discussion)

The last point was to be extracted to a different story because we did not wanted to force the user to have a specific version of Spark and have the spark dependency on the Data Access module, but actually there is already a compile only dependency for spark-core and spark-sql 2.11. So I added it either way to discuss the ups and downs of such a solution in this review.