fix: validation for ``array`` and ``object`` typed partition columns were broken
fix flaky tests and possible NPE in blob container
update changes to reflect release of 0.38.5
Merge pull request #883 from crate/l/merge-0.38.5

L/merge 0.38.5
implement "alter table add column"
refactor create table statement analyzer

in order to

 * share code between create table and alter table add column
 * avoid empty lists in the mapping which break merging of the mappings
add column: validate nested columns and only allow add columns on non-system tables