Revert Typescript migration (#90)

[legobeat]

• This reverts: Typescript migration #90

Notes:

• This does not revert bumps of devDependencies jest, @types/jest
• The changes in Bump all dependencies #94 have been retained (brought into index.js)

[socket-security]

Removed dependencies detected. Learn more about Socket for GitHub ↗︎

🚮 Removed packages: @metamask/eslint-config-typescript@11.1.0, @types/node@18.18.0, @typescript-eslint/eslint-plugin@6.7.3, @typescript-eslint/parser@5.62.0, eslint-plugin-jsdoc@46.8.2, ts-jest@29.1.1, ts-node@10.9.1, typedoc@0.23.28, typescript@4.9.5

[Gudahtt]

LGTM! I compared this branch to v6.0.0 and it looks like the only changes are to the minimum supported Node.js version and the dependency bumps (and one minor code refactor related to one of these bumps)

[legobeat]

Backported to v6 in #102