Feature Request: Support longer name prefixes

[BC-atJG]

Description

When defining an Agent Image the Name Prefix is currently capped at 12 characters. It would be greatly appreciated if they could be longer to support more descriptive names.

For example, I was wanting to use ubuntu18-small- as a prefix, but needed to use lin-sm- in order to fit.

Environment

• TeamCity version: TeamCity Enterprise 2021.1.1 (build 92714)
• Azure plugin version: 0.9.8

Diagnostic logs

To investigate the problems it worth look at the teamcity-agent.log agent log file and teamcity-clouds.log server log file. You could file an issue in the TeamCity tracker and privately attach these file for investigation by TeamCity team.

[VladRassokhin]

Right now it's limited to be 100% sure that after appending incremental suffix, the hostname for Windows VMs won't exceed the limit (15 characters).
Though, for Linux that limit is indeed strange.