Removed unused classes and tests

[olenagerasimova]

Part of #440
Cleaned up unused classes, tests and some code from used classes.

[codecov]

Codecov Report

Merging #484 (7aae84e) into master (92815b3) will increase coverage by 0.95%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master     #484      +/-   ##
============================================
+ Coverage     86.96%   87.91%   +0.95%     
+ Complexity      462      382      -80     
============================================
  Files            65       49      -16     
  Lines          2201     1639     -562     
  Branches        139      111      -28     
============================================
- Hits           1914     1441     -473     
+ Misses          263      179      -84     
+ Partials         24       19       -5     

Impacted Files	Coverage Δ
src/main/java/com/artipie/rpm/meta/XmlPackage.java	94.73% <ø> (+12.91%)	⬆️
src/main/java/com/artipie/rpm/pkg/FilePackage.java	96.96% <ø> (-3.04%)	⬇️
src/main/java/com/artipie/rpm/NamingPolicy.java	80.00% <0.00%> (-20.00%)	⬇️
...ain/java/com/artipie/rpm/StandardNamingPolicy.java	81.81% <0.00%> (-18.19%)	⬇️
.../main/java/com/artipie/rpm/meta/XmlWriterWrap.java	29.68% <0.00%> (-12.50%)	⬇️
src/main/java/com/artipie/rpm/meta/XmlRepomd.java	81.96% <0.00%> (-1.64%)	⬇️

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[genryxy]

@olenagerasimova thanks, looks good to me