Moving function indexing to init request

[gavin-aguiar]

Description

Included in this PR:

• In the dispatcher, indexing is moved from metadata request to init request and env reload request and results are stored and returned in the metadata response
• Indexing in init is behind an flag: ENABLE_INIT_INDEXING
• Unit tests, e2e tests and consumption tests

Fixes #

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PR information

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• There are a small number of commits, each of which has an informative message. This means that previously merged commits do not appear in the history of the PR. For information on cleaning up the commits in your pull request, see this page.
• If applicable, the PR references the bug/issue that it fixes in the description.
• New Unit tests were added for the changes made and CI is passing.

Quality of Code and Contribution Guidelines

• I have read the contribution guidelines.

[codecov]

Codecov Report

Attention: Patch coverage is 92.85714% with 2 lines in your changes are missing coverage. Please review.

Project coverage is 85.30%. Comparing base (c68f88b) to head (916ffb2).

Files	Patch %	Lines
azure_functions_worker/dispatcher.py	92.30%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##              dev    #1446      +/-   ##
==========================================
+ Coverage   85.10%   85.30%   +0.19%     
==========================================
  Files          35       35              
  Lines        1974     1987      +13     
  Branches      374      379       +5     
==========================================
+ Hits         1680     1695      +15     
+ Misses        218      216       -2     
  Partials       76       76              

Flag	Coverage Δ
unittests	85.25% <92.85%> (+0.19%)	⬆️

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[codecov-commenter]

Codecov Report

Attention: Patch coverage is 82.05128% with 7 lines in your changes are missing coverage. Please review.

Project coverage is 85.23%. Comparing base (c68f88b) to head (18d6231).

Files	Patch %	Lines
azure_functions_worker/dispatcher.py	81.08%	6 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##              dev    #1446      +/-   ##
==========================================
+ Coverage   85.10%   85.23%   +0.12%     
==========================================
  Files          35       35              
  Lines        1974     1998      +24     
  Branches      374      378       +4     
==========================================
+ Hits         1680     1703      +23     
- Misses        218      219       +1     
  Partials       76       76              

Flag	Coverage Δ
unittests	85.18% <82.05%> (+0.12%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[vrdmr]

LGTM