[FEATURE] add dynamic destionation paths to config

[nydragon]

Is your feature request related to a problem? Please describe.
I have started using this project yesterday and found myself confronted with the lack of support for dynamic paths.
By that I mean that every destination for a file is static and will not change.

Describe the solution you'd like
Allow path expansions, shell style:

"firefox/cookie_cache"="~/.mozilla/firefox/**.default-release/permissions.sqlite"

** being in this case gibberish that is firefox version dependent, at least I assume.
And the deploy could fail if the expansion is ambiguous.

I wasn't able to find any crate that already does this for you,

Describe alternatives you've considered
Alternatively it would be a possibility to add string interpolation to the .toml files and allow shell script evaluation.

"firefox/cookie_cache"="{{ find ~/.mozilla/firefox/ -name \"permissions.sqlite\"  }}"

[SuperCuber]

This is very similar to #61 , and would be covered by it.
Sadly I don't have much bandwidth to work on the project nowadays, so a PR implementing this would be greatly appreciated.

For your use case, you can run a pre-deploy script with something like

rm -f ~/.mozilla/firefox/actual-default-release
ln -s ~/.mozilla/firefox/*.default-release ~/.mozilla/firefox/actual-default-release

then deploy into actual-default-release folder.

Add protection against zero or multiple matches as you see fit :)

[nydragon]

Alright, thank you a lot for your feedback!

I will start looking at the code and how to implement the feature mentioned in #61 and this issue.
However it will take some time as I do not have a lot of experience in Rust and I don't have an
enormous bandwidth either. But I suppose there isn't much urgency.