* added a TeamCity icon and updated simple-icons.json accordingly
* modified TeamCity icon
* amended the icon to comply with existing JetBrains logo and product logos
* updated the icon to match the rest of available JetBrains product icons, updated source property to link to the brand logos download page
* replaced tabulation with spaces
Co-authored-by: Fedor Rumyantsev <fedor.rumyantsev@jetbrains.com>
