Extend getsourcecode API view with new output fields

[vbaranov]

Closes #751

Motivation

getsourcecode API endpoint doesn't return all fields Blockscout reserved for a smart-contracts in DB

Changelog

Add the new fields to the view:

• constructor_arguments
• external_libraries
• optimization_runs
• evm_version

Configure hiding of output fields in the view if they are empty

Checklist for your Pull Request (PR)

• I added an entry to CHANGELOG.md with this PR
• If I added new functionality, I added tests covering it.
• If I fixed a bug, I added a regression test to prevent the bug from silently reappearing again.
• I checked whether I should update the docs and did so by submitting a PR to https://github.com/blockscout/docs
• If I added/changed/removed ENV var, I submitted a PR to https://github.com/blockscout/docs to update the list of env vars at https://github.com/blockscout/docs/blob/master/for-developers/information-and-settings/env-variables.md and I updated the version to master in the Version column. Changes will be reflected in this table: https://docs.blockscout.com/for-developers/information-and-settings/env-variables.
• If I add new indices into DB, I checked, that they are not redundant with PGHero or other tools

[coveralls]

Pull Request Test Coverage Report for Build 23f16034-99dc-4dfa-9a63-946ab8f3a244

• 20 of 22 (90.91%) changed or added relevant lines in 1 file are covered.
• 2 unchanged lines in 1 file lost coverage.
• Overall coverage increased (+0.03%) to 75.124%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
apps/block_scout_web/lib/block_scout_web/views/api/rpc/contract_view.ex	20	22	90.91%

Files with Coverage Reduction	New Missed Lines	%
apps/block_scout_web/lib/block_scout_web/controllers/chain/market_history_chart_controller.ex	2	71.43%

Totals
Change from base Build 24fc869e-c854-4191-9ac9-0087b47c143a:	0.03%
Covered Lines:	5297
Relevant Lines:	7051

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💛 - Coveralls

[ayrat555]

there is no tests for ExternalLibraries and ConstructorArguments fields

[vbaranov]

@ayrat555 requested tests have been added bde993f

[ayrat555]

one style comment. Otherwise, LGTM