quill-finagle-mysql: add connection init sql support

[krrrr38]

Problem

From finagle 20.4.1, finagle-mysql support connection init request. It is same feature with HikariCP connection-init-sql.

Currently FinagleMysqlContextConfig doesn't support this feature.

Solution

Add connectionInitSql config for FinagleMysqlContextConfig.

Checklist

• Unit test all changes
• Update README.md if applicable
• Add [WIP] to the pull request title if it's work in progress
• Squash commits that aren't meaningful changes
• Run sbt scalariformFormat test:scalariformFormat to make sure that the source files are formatted

@getquill/maintainers

[CLAassistant]

All committers have signed the CLA.

[juliano]

Closed once finagle modules have been dropped