Migrate to Webpack@5

[vbaranov]

Motivation

A version of Webpack is outdated

Changelog

Migrate client-side build of the application to the latest version of Webpack@5

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 cffefd3a0ac7ef19eda234bcefd39e837a6cbd8f-PR-3489

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 8 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.8%) to 66.904%

---

Files with Coverage Reduction	New Missed Lines	%
lib/block_scout_web/controllers/chain/market_history_chart_controller.ex	2	71.43%
lib/block_scout_web/checksum_address.ex	6	55.56%

Totals
Change from base Build 183fa6d56898b44d1c98e98486227fa3a15565f6:	-0.8%
Covered Lines:	2064
Relevant Lines:	3085

---

💛 - Coveralls