Refactor and add documentation komodo fetch

[jonathan-eq]

It is difficult to wrap your head around what is happening in the fetch module if you are new to the tool.
The functions are doing too much, and they are poorly documented.
Try splitting them into smaller, self explanatory functions. This would make it easier to read and test.

[jonathan-eq]

Update, komodo fetch was actually not too bad, so this issue might not be relevant.