expands the `purge` command to accept args for
purging mail folders, calendars, or both. This
allows the test cleanup to ensure we aren't over-
populating either mail folders or calendars, thus
blocking CI actions
swaps the corso go module from github.com/
alcionai/corso to github.com/alcionai/corso/src
to align with the location of the go.mod and
go.sum files inside the repo.
All other changes in the repository update the
package imports to the new module path.
Adds the base CLI integration tests for backup, list, details,
and restore. Also refactors out the global root command
value in favor of a ctx-bound reference so that tests may
control safely overwriting stdout to scrutinize output.
Adds the basic cli-based backup integration test.
Due to discovering some corner cases about panic
conditions and other error handling in bad runtime
state, updates many other packages for safety.
