Allow resizing of Mokku frames

[cgraham-rs]

As a user I want to manually resize the various frames in the Mokku UI.

In the Mocks tab there's a method/url frame on the left, and the mock detail frame on the right. Viewing on a 4k monitor at various scaling the mock detail is always a tiny fraction of the screen. However, that's the frame I need to use to edit the mocked data.

[mukuljainx]

Hi @cgraham-rs,

Thanks for the suggestion, pretty useful on big screens, will be implemented in the next major release.

[mukuljainx]

Added in v2.0.0