Rm LocalAppSnippet.setup

[mishig25]

Follow up to #778 and #942

After #942, I've realized that a better absteraction/generalisation is just to make LocalAppSnippet.content: string | string[] & remove LocalAppSnippet.setup altogether. Instead put what was in LocalAppSnippet.setup as the first item in LocalAppSnippet.content string array

[Vaibhavs10]

No strong feelings but I do have a preference for explicit declerations over implicit.

Could we maybe add a comment in code here/ somewhere that the first line corresponds to setup? - We get a few contributors for LocalApps now, it'd be good to make it easier for them to understand.

[ngxson]

In fact, my initial idea was to have the ability to hide the setup section if user already installed the package. It will be useful if the setup is multi-steps, so user can optionally hide it to gain some space.

Also agree with @Vaibhavs10 that explicitly having setup is more intuitive for contributors.

[julien-c]

yes let's keep it imo