Compiled for Outward version from July 11, 2019. 

This mod is simply a recompiled copy of Assembly-CSharp.dll which has a particular weight function set so it always returns -1 instead of an actual weight limit, which the rest of the game's code interpret as having no limit. Huge thanks to  bob1234567 not maintaining his mod as the reason I'm posting this.

Warnings/Caution:

1. The Outward game scripts/code currently does not take kindly to hoarding, there is apparently a bug where loading times grow exponentially once a certain number of items are in your town/area. Be careful not to hoard what you don't need, and sell most items you don't immediately need, at least until they patch the "Loading Items" bug.

2.  Because this modifies a key DLL file, it is extremely likely to break with every minor patch. But anyone can manually mod the game themselves using dnSpy. In fact, I highly suggest you implement this mod yourself instead of downloading from here by:

-Download dnSpy
-Open the Assembly-CSharp.dll file with dnSpy.
-Find the "ItemContainer" class and right click and Edit Class. 
-Around line 715 is a function named ContainerCapacity. 
-Modify it to look like this (copy/paste to replace the entire function would work). 

    public float ContainerCapacity
    {
        get
        {
            return -1f;
        }
    }

Hit Compile then Save All.