Implement L2 Norm for morphology transforms

[Morgane55440]

this PR has been made following the issue #314 : Implement L2 Norm for morphology transforms

this PR seeks to integrate the L2 Norm for morphology operation, by expanding the Norm Enum to include L2, and updating all the functions which use this Enum to support the change. before :

pub enum Norm {
    /// Defines d((x1, y1), (x2, y2)) to be abs(x1 - x2) + abs(y1 - y2).
    /// Also known as the Manhattan or city block norm.
    L1,
    /// Defines d((x1, y1), (x2, y2)) to be max(abs(x1 - x2), abs(y1 - y2)).
    /// Also known as the chessboard norm.
    LInf,
}

after:

pub enum Norm {
    /// Defines d((x1, y1), (x2, y2)) to be abs(x1 - x2) + abs(y1 - y2).
    /// Also known as the Manhattan or city block norm.
    L1,
    /// Defines d((x1, y1), (x2, y2)) to be sqrt((x1 - x2)^2 + (y1 - y2)^2).
    /// Also known as the euclidian norm.
    /// when working in integer distances, we take the smallest 
    /// greater integer value, also know as 'ceiling'
    /// example : d((0,0),(1,2)) = ceil(sqrt(1+2^2)) = ceil(2.236...) = 3
    L2,
    /// Defines d((x1, y1), (x2, y2)) to be max(abs(x1 - x2), abs(y1 - y2)).
    /// Also known as the chessboard norm.
    LInf,
}

on top of adding tests for the new norm, this PR also adds a couple tests for the other norms, in particular when erode and dilate are called with a distance k of 0.

[theotherphil]

Please can you run cargo fmt on your PR - formatting is checked in the pre-commit tests.

[Morgane55440]

Please can you run cargo fmt on your PR - formatting is checked in the pre-commit tests.

done - just learned cargo fmt is a thing today

[theotherphil]

After inlining the unnecessary wrapper functions this looks good to me, thanks!

[Morgane55440]

done !

[theotherphil]

Thanks!