Reintroduce fsck

[dominikschulz]

Fixes #711

[codecov]

Codecov Report

Merging #721 into master will decrease coverage by 0.55%.
The diff coverage is 10.75%.

@@            Coverage Diff             @@
##           master     #721      +/-   ##
==========================================
- Coverage   62.97%   62.42%   -0.55%     
==========================================
  Files         161      164       +3     
  Lines        8749     8839      +90     
==========================================
+ Hits         5509     5517       +8     
- Misses       2591     2673      +82     
  Partials      649      649

Impacted Files	Coverage Δ
pkg/backend/storage.go	100% <ø> (ø)	⬆️
pkg/backend/crypto.go	100% <ø> (ø)	⬆️
pkg/action/fsck.go	0% <0%> (ø)
pkg/store/root/fsck.go	0% <0%> (ø)
pkg/backend/crypto/gpg/cli/gpg.go	70.31% <0%> (-3.46%)	⬇️
pkg/backend/crypto/plain/backend.go	97.26% <0%> (-2.74%)	⬇️
pkg/backend/crypto/gpg/cli/keyring.go	30% <0%> (-1.03%)	⬇️
pkg/backend/crypto/xc/utils.go	71.64% <0%> (-2.2%)	⬇️
pkg/store/sub/fsck.go	0% <0%> (ø)
pkg/store/root/list.go	45.1% <100%> (ø)	⬆️
... and 5 more

---

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 85507b0...91f3a6b. Read the comment docs.