`[Exiled::Events]` Added new commands for installing plugins, changing or printing config values

[VALERA771]

[Exiled::API] Added extension

StringExtensions::FromSnakeCase(string)

for converting strings from snake_case to NotSnakeCase

[VALERA771]

Install command tested. Other will be tomorrow

[VALERA771]

All commands have been tested

[VladTheCow]

Why DoNotMerge?

[Misfiy]

@NaoUnderscore (as asked by vlad) why do not merge?

[NaoUnderscore]

Because I'd like to wait before merging Plugin Manager/Installer-like features. We're going to implement it through our Web APIs.

[VALERA771]

@NaoUnderscore