Cleaner layout for Instance overview

[joepavitt]

Description

First step in #2487 - this makes the overview screen cleaner to look at and separates the "info" from the "specs" of the instance.

After:

Before:

Checklist

• I have read the contribution guidelines
• Suitable unit/system level tests have been added and they pass
  • Structural & styling changes only

[codecov]

Codecov Report

Merging #2550 (1c208ae) into main (929a774) will decrease coverage by 73.06%.
Report is 3 commits behind head on main.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##             main   #2550       +/-   ##
==========================================
- Coverage   74.63%   1.58%   -73.06%     
==========================================
  Files         228     495      +267     
  Lines        9164   17789     +8625     
  Branches     1891    4152     +2261     
==========================================
- Hits         6840     282     -6558     
- Misses       2324   17507    +15183     

Flag	Coverage Δ
backend	?
frontend	1.58% <0.00%> (?)

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Files Changed	Coverage Δ
frontend/src/pages/instance/Overview.vue	0.00% <0.00%> (ø)

... and 443 files with indirect coverage changes