[DOCS] Adds breaking changes for 7.8#68588

Merged

gchaps merged 6 commits intoelastic:7.xfrom gchaps:docs/breaking-changes-7.8

Jun 15, 2020

+525

Commits on Jun 8, 2020

[DOCS] Adds breaking changes for 7.8
gchaps
committed

Commits on Jun 9, 2020

[DOCS] Adds more breaking changes
gchaps
committed

Commits on Jun 10, 2020

Commits on Jun 11, 2020

[DOCS] Incorporates review comments
gchaps
committed

Commits on Jun 15, 2020

[DOCS] Fixes links so they work in Install doc
gchaps
committed