ENH: add action to fetch Kaiju DBs

[misialq]

Closes #41.
Requires bokulich-lab/q2-types-genomics#50.

[codecov]

Codecov Report

Merging #61 (3ce7c26) into main (01db060) will increase coverage by 0.05%.
The diff coverage is 98.55%.

@@            Coverage Diff             @@
##             main      #61      +/-   ##
==========================================
+ Coverage   97.69%   97.74%   +0.05%     
==========================================
  Files          32       35       +3     
  Lines        2038     2172     +134     
==========================================
+ Hits         1991     2123     +132     
- Misses         47       49       +2     

Files	Coverage Δ
q2_moshpit/__init__.py	100.00% <100.00%> (ø)
q2_moshpit/kaiju/__init__.py	100.00% <100.00%> (ø)
q2_moshpit/kaiju/database.py	100.00% <100.00%> (ø)
q2_moshpit/plugin_setup.py	100.00% <100.00%> (ø)
q2_moshpit/kaiju/tests/test_database.py	96.96% <96.96%> (ø)

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[VinzentRisch]

Everything looks good.
I ran the method with plasmids, viruses and fungi and all work with no problems.
Progress bar works too and is actually really useful i should add that to fetch-card-db in q2-amr.