[RI-7040] RiIcon refactor (#4727)

* replace EuiIcon in ExternalLink.tsx

* remove console.log

* temp

* update Icon.tsx, RiIcon.tsx

* add isSvg prop

* replace EuiIcon

* add some icons

* refactor icons

* replace icons

* replace icons

* replace icons

* replace icons

* remove icon files

* fix SlowLogTable.spec.tsx matcher

* move sidebar icons

* move options icons

* move modules icons

* replace Icon with RiIcon

* remove todo comment

* remove todo comment

* add back icons

* fix issues after rebase

* remove usage of htmlIdGenerator

* remove unused files, fix tests

* RI-7040: refactor icons to reduce technical debt

* include missing icon

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Co-authored-by: pd-redis <[email protected]>

Author: KrumTy