Fix importer for directories - now a seperate import menu item

[astrofrog]

@keflavich - this should fix the issues you were seeing under Linux

[codecov]

Codecov Report

Merging #2080 into master will increase coverage by 0.03%.
The diff coverage is 92.85%.

@@            Coverage Diff             @@
##           master    #2080      +/-   ##
==========================================
+ Coverage   87.95%   87.99%   +0.03%     
==========================================
  Files         243      245       +2     
  Lines       22090    22101      +11     
==========================================
+ Hits        19430    19448      +18     
+ Misses       2660     2653       -7

Impacted Files	Coverage Δ
glue/core/data_factories/__init__.py	100% <ø> (ø)	⬆️
glue/dialogs/data_wizard/qt/data_wizard_dialog.py	93.9% <100%> (+0.31%)	⬆️
glue/io/qt/directory_importer/__init__.py	100% <100%> (ø)
...lue/io/qt/directory_importer/directory_importer.py	80% <80%> (ø)
glue/app/qt/application.py	78.5% <0%> (+0.35%)	⬆️
glue/config.py	84.88% <0%> (+1.16%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update e8689ac...d02fdcd. Read the comment docs.