Combine and refine dependency injection patterns

[gyermolenko]

ref #284

What this PR does:

• combine dependency injection patterns into one file since they have a lot of common boilerplate
• add tests (and remove old ones)
• turn injected classes into functions
• update description
• update readme

[codecov-io]

Codecov Report

Merging #285 into master will decrease coverage by 0.79%.
The diff coverage is 100%.

@@            Coverage Diff            @@
##           master     #285     +/-   ##
=========================================
- Coverage   72.99%   72.19%   -0.8%     
=========================================
  Files          62       57      -5     
  Lines        2177     2115     -62     
=========================================
- Hits         1589     1527     -62     
  Misses        588      588

Impacted Files	Coverage Δ
patterns/dependency_injection.py	100% <100%> (ø)

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