add a (very) simple install script to resolve #30

[veswill3]

This should allow an install and update for the most simple case.

[primis]

While the idea of an install file would be a great addition, this one has a few problems:

• Git has an api to grab latest release built in (GET /repos/:owner/:repo/releases/latest)
• Rather than curl each individual file, grabbing a release tarball and extracting to a temp folder would be better (and scales easier)
• bash's completion directory should be found using the method from the readme: pkg-config --variable=completionsdir bash-completion
• Previous Installation check and uninstall should use which notes to determine the install directory (so you don't end up with two on accident)
• This file also doesn't create a ~/.config/notes directory, which is fine honestly, but I would put the config.example in it on a proper install.
• Uninstall should be available to be run without a re install (ie, to wipe away notes)

While this file gets the job done, it does only handle a single use case, very statically. I would not suggest accepting this PR.

[veswill3]

Thanks for the comments. I will make updates and we can review again. It unfortunately may be a few days until I get internet again though. I won't forget.