Add Lido-Exporter app

[AntiD2ta]

Changes:

• Add new application lido-exporter to scrape data from Lido CSM smart contracts and export it as Prometheus metrics.
• Refactor E2E test suite
• Add interaction code for the VEBO contract
• Remove courtney dependency (it is better to rely on real test coverage and we are not really using the tool features to hide code)

Types of changes

What types of changes does your code introduce?
Put an x in the boxes that apply

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Other (please describe):

Testing

Requires testing

• Yes
• No

In case you checked yes, did you write tests?

• Yes
• No

Further comments (optional)

Since there are two apps in the repo now, we have to create a PR after merging this to move app-specific packages to the app folder (the lido-exporter app has its own cli folder for example). The e2e folder is respecting this new structure and there is a suite implementation for each app (sedge and lido-exporter).

#406 updates sedge's e2e test suite and test cases. The CI will likely fail for this PR since some critical changes and fixes are in #406.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 17.64706% with 252 lines in your changes missing coverage. Please review.

Project coverage is 44.34%. Comparing base (000cc79) to head (2ecb064).

Files with missing lines	Patch %	Lines
cmd/lido-exporter/cli/lido_exporter.go	0.00%	92 Missing ⚠️
cmd/lido-exporter/metrics/metrics.go	0.00%	41 Missing ⚠️
cmd/lido-exporter/metrics/penalties.go	0.00%	31 Missing ⚠️
cmd/lido-exporter/metrics/exit_requests.go	0.00%	18 Missing ⚠️
cmd/lido-exporter/metrics/keys.go	0.00%	16 Missing ⚠️
cmd/lido-exporter/metrics/bonds.go	0.00%	15 Missing ⚠️
cmd/lido-exporter/metrics/node_operator.go	0.00%	14 Missing ⚠️
cmd/lido-exporter/metrics/rewards.go	0.00%	12 Missing ⚠️
cmd/lido-exporter/main.go	0.00%	6 Missing ⚠️
configs/networks.go	58.33%	5 Missing ⚠️
... and 1 more

Additional details and impacted files

@@             Coverage Diff              @@
##           develop     #411       +/-   ##
============================================
- Coverage    88.06%   44.34%   -43.73%     
============================================
  Files           99      114       +15     
  Lines         5673     9797     +4124     
============================================
- Hits          4996     4344      -652     
- Misses         553     4991     +4438     
- Partials       124      462      +338     

Flag	Coverage Δ
unittests	44.34% <17.64%> (-43.73%)	⬇️

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.

[stdevMac]

We should add documentation either on this PR or in other, about this new app