cache: adding caching on look_up repository (PROJQUAY-6472)

[Sunandadadi]

This PR caches the response of model.repository.get_repository as a json object instead of picking as done in #2515.

[codecov]

Codecov Report

Attention: 3 lines in your changes are missing coverage. Please review.

Comparison is base (2410c7a) 70.56% compared to head (99a94cf) 70.68%.
Report is 25 commits behind head on master.

Files	Patch %	Lines
data/cache/cache_key.py	75.00%	1 Missing and 1 partial ⚠️
endpoints/v2/manifest.py	75.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2521      +/-   ##
==========================================
+ Coverage   70.56%   70.68%   +0.12%     
==========================================
  Files         434      434              
  Lines       39826    39940     +114     
  Branches     5164     5183      +19     
==========================================
+ Hits        28102    28232     +130     
+ Misses      10101    10080      -21     
- Partials     1623     1628       +5     

Flag	Coverage Δ
unit	70.68% <88.88%> (+0.12%)	⬆️

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[syed]

lgtm