Add licence file and headers

LICENSE

...afetch/graphql/TangoArchivingGQLExtractorApplication.java

...iving/datafetch/graphql/config/ApplicationProperties.java

...il/archiving/datafetch/graphql/config/DatabaseConfig.java

...ing/datafetch/graphql/config/DatabaseConfigFromTango.java

...chiving/datafetch/graphql/datasource/ArchivingApiDAO.java

...hiving/datafetch/graphql/datasource/CustomGQLMetrics.java

...chiving/datafetch/graphql/datasource/infra/IDatabase.java

...ng/datafetch/graphql/datasource/infra/LegacyDatabase.java

...atafetch/graphql/datasource/infra/TimeseriesDatabase.java

...l/archiving/datafetch/graphql/domain/AttributeValues.java

...hiving/datafetch/graphql/domain/TangoAttributeFormat.java

...rchiving/datafetch/graphql/domain/TangoAttributeInfo.java

...g/datafetch/graphql/domain/values/LegacyDbDataMapper.java

...hiving/datafetch/graphql/domain/values/ReductionType.java

...chiving/datafetch/graphql/domain/values/SamplingType.java

...datafetch/graphql/tango/server/TangoDeviceGQLFetcher.java

...iving/datafetch/graphql/types/JsonScalarRegistration.java

...iving/datafetch/graphql/types/LongScalarRegistration.java

...atafetch/graphql/utils/RequestLoggingInstrumentation.java