chore: rename bench

[18alantom]

ToDo:

• [x] UI labels, titles, etc
• [x] File and folder names
• [ ] In code references (will either do it incrementally or in a future PR)

"Bench" will be renamed such that:

• All user-facing labels will be called "Bench Group"
• All code references will either be group or releaseGroup.

Why?: "Bench" on the dashboard refers to the Release Group doctype. This causes immense confusion because there also exists a Bench doctype.

The objects of Bench are shown UI side (under the Site list), but they can't be called "Bench" because that already refers to something else.

This ends up being a hinderance when it comes to support, writing documentation, etc. It is also a hinderance when it comes to development because in dashboard code Release Group objects are referred to both as bench and as release group. This asinine naming causes conceptual-confusion on all sides and we end up with a kind of tower-of-babel like problem.

Finally, if we are to show Bench analytics on the dashboard, we'd be worsening the problem by using other terms instead of "Bench". So this is a necessary pre-req.

Note: as of now benches/bench-XXXX route will remain the same.

Notes:

• Avoid use unnecessary use of "Bench", eg: "Scheduling bench deploy" -> "Schedule deploy"
• Not altered: CreateSiteForMarketplaceApp.vue, seems to refer to the Doctype SiteGroupDeploy which has "Bench Deploy *" as one of its status, not sure what it refers to here.

[18alantom]

Broken test unrelated to PR. Will complete the last to-do (renaming in code references, mainly variables) in the next PR. Merging this.