Align ecosystem / package colors with GitHub Linguist

[sschuberth]

To make developers feel more at home, we should consider aligning our ecosystem / package colors to those defined by GitHub Linguist.

However, note that there still would be a difference as to how GitHub and ORT Server display the colors for a given Git repository: While GitHub looks at the file extensions of all contained files, ORT (Server) looks at the file extensions of the definition files only. That is, a Kotlin project managed by Gradle would be (mostly) a Kotlin "thing" for GitHub, but a Gradle "thing" for ORT (Server).

[Etsija]

These colors seem to be defined for languages, not package managers, so I assume a map between those two would also need to be done.

[Etsija]

FYI, the current colors were designed with the kind help from ChatGPT, which made pretty good, if not perfect, guesses as to what package managers / ecosystems are mostly handling projects coded in which languages. That mapping could be used here.

[sschuberth]

These colors seem to be defined for languages, not package managers, so I assume a map between those two would also need to be done.

More generally, the colors are defined per file extensions, no matter whether they belong to a language or package manager. For example, Linguist does define a color for Gradle files.