[OPPM] Ability to manage and use locally registered repositories

[stsimonas]

Right now, when specifying a package/repository locally, you have to add both the repository and the package details in the configuration file.

What about expanding the functionality and the API to have the ability of managing and using just locally registered repositories (without specifying package details locally)?
Where those repositories would be queried (on update/list) for packages available in them.

Example:

oppm localrepo add <userName/repositoryName>
oppm localrepo list
oppm localrepo remove <userName/repositoryName>

And in the local configuration file:

{
    --default installation path
    path="/usr",
    --Additional repositories and packages go here, for correct package syntax, check https://github.com/OpenPrograms/Vexatos-Programs/blob/master/op-manager/etc/example-config.cfg
    repos={
        ["YourUsername/YourRepo"],

        ["AnotherUserYourTrust/AnotherRepository"],

        ["ThirdUser/ThirdRepo"] = {
            ["FullySpecifiedLocalPackage"] = {
                ...
            }
        },
    }
}

[Vexatos]

While this suggestion sounds very good, there always is the problem that I try to have OPPM as small of a program as possible. The more features I add, the more "bloated" it gets. I'll think about it.

[reinei-zz]

Suggestion: Get a plugin system so the user can decide whether or not he wants a bloated, but feature rich environment? (I know this should be another Issue ...)

[Hawk777]

Seems like this was done in f8dce5a?