Move the ITEMS_TO_COPY list out of the code

[dgou]

@peterkaminski
Built this on top of #7 to leverage some of the code there and to extend the idea of "simple text files".

Thoughts and ruminations:

1. I am liking have the external files.
2. Using .txt to be windows friendlier, but it does feel odd to use that extension on Linux.
3. On my Linux system, there isn't a single 'config' as was listed in the code, but just a bunch of config files in the root directly. I pretty much added all of them in as a starting point for discussion.
4. How to let users customize and / or extend the list?
5. How to list exceptions or carve-outs when copying a big directory like plugins?

For 5) I feel as if there is an existing solution we should be able to borrow, but it is late enough that I can't think of it. .gitignore is one "style", but that has some sharp-edges that I catch myself on, and it's hard to use it to do a partial carve out. Globs seem like a reasonable "high level" hand-wave answer, but I feel like there are other tools that do this and it would be nice to borrow from that rather than reinvent.

For 4) I have two ideas:
a) Read an optional second file (copy-list-custom.txt (names are hard)) after reading the main copy-list.txt. That is easy when all you want to do is extend, but if you want to also excise (such as README.md) that is trickier.
b) Ship a copy-list-template.txt file that is only read if the user doesn't create their own copy-list.txt file to use. And in this case I would add support for a new line type @filename that causes the contents of filename to be included at that point, so that a user who want to extend the template could reference it by name instead of having to keep it manually up to date on each new release (not expecting a lot of changes, but want to permit it).

Hopefully this makes sense on a late Friday, wanted to have something concrete to drive the discussion.
While I based this on #7, I figure that PR can merge separately unless we want to go whole-hog on a Big Fat Greek Wedding Configuration YAML.

[dgou]

Yeah, this strip() should be above the not line, that's fixed in a later commit.

[dgou]

Some additional thoughts/notes/bread-crumbs:
For 5) probably a good idea to have a "tell me what matches", so not even a diff, just a "what would you want to copy from the source Vault without regard to how it lines up with any particular destination vault(s)" to make fine-tuning the selections easier.
After stack overflow searching failed again, I started thinking about just having simple ordered list of items, each one a simple pattern of things to either add to the list to copied, or removed from it.

Include: plugins
Exclude: plugins/abc
Include: foo
Exclude: foo/bar
Include: foo/bar/templates

Hmm, seems like something like that should be in PyPI already :-)

[dgou]

Made #10 to implement spike of include/exclude idea as a stand-alone script rather than complicating this PR with more commits.

[dgou]

Closing this spike, we decided to go in a different direction.