[QUEST] v7 Release

[bertdeblock]

When fixing CI over in https://github.com/ember-cli/ember-cli-htmlbars/pull/775, I noticed this project has a few fallbacks in place for older versions of various packages (ember-cli, ember-source, ember-cli-babel, ember-cli-htmlbars-inline-precompile, ...). Maybe it's a good idea to clean those up, to make maintenance a bit easier?

Suggestion checklist:

• [ ] Remove support for Node v12 and v14: https://github.com/ember-cli/ember-cli-htmlbars/pull/777
• [ ] Add support for Node v16, v18 and v20: https://github.com/ember-cli/ember-cli-htmlbars/pull/777
• [ ] Remove globalThis check (always available since Node v12): https://github.com/ember-cli/ember-cli-htmlbars/pull/777
• [ ] Remove support for ember-cli versions below v3.13
• [ ] Remove support for ember-source versions below v3.28
• [ ] Remove support for ember-cli-babel versions below v7.11
• [ ] Remove fallback for ember-cli-htmlbars-inline-precompile and/or error when present?