Request: move the tabColor setting from profile to color-scheme

Correct me if I am wrong

- You can change the color-scheme of an open tab
- But you can not change the profile of an open tab
- The color of the tab is set with tabColor in the profile (can be also done manually)

In my use case I am opening ssh sessions to different servers. Often 2-3 tabs point at one server and 2-3 other tabs point at another.
I want to mark these tabs so I know at a glance who is who

- I can change the color-scheme of a tab so that I instinctively know which server I am currently sending commands to.
- I can change the tab-color manually, so that I know which hidden tab goes to which server.

But that's me choreographing 2 separate actions to achieve one objective.
Logically the tab-color can (should) be part of the color-scheme.

Start by tracing where tabColor is defined under profiles and where color-scheme changes are handled for open tabs. Confirm how manual tab-color changes currently work. Done means changing an open tab's color-scheme also applies its tab color, so users do not need two separate actions.

Written by the indexing model from the issue text.