Optimize performance

[microstudi]

This is an attempt to improve performance in general when using Awesome, in some case can be noticable as is reported in #350

• Memoize cache_hash for the overriden cell
• Memoize AwesomeHelper at the global request object. This prevents to repeat queries as helpers in rails are different instances in each view

Depending on the context, I've been able to reduce view rendering time in the proposal index page:

no optimization	memoize cache_hash	memoize cache_hash and Helpers at class
11317ms	7927ms	5543ms

This number are in the development app, with no cache activated.
When cache is activated (bin/rails dev:cache) performance is even better than the original Decidim (until decidim/decidim#1370 is merged)

[codecov]

Codecov Report

Attention: Patch coverage is 54.28571% with 16 lines in your changes missing coverage. Please review.

Project coverage is 66.52%. Comparing base (6c9476c) to head (c7866f1).
Report is 9 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/decidim/decidim_awesome/awesome_helpers.rb	33.33%	14 Missing ⚠️
...ecidim/decidim_awesome/proposal_l_cell_override.rb	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #358      +/-   ##
==========================================
- Coverage   68.85%   66.52%   -2.33%     
==========================================
  Files          80       72       -8     
  Lines        2106     1894     -212     
==========================================
- Hits         1450     1260     -190     
+ Misses        656      634      -22     

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