Add an ability to update scriptlets and redirect resources without updating whole program

[AdamWr]

At the moment we have to wait to use some new/improved scriptlets (or bug fixes) until AdGuard app will be updated. So I think that it would be nice, if scriptlets (and extended CSS) library could be updated like filters/extensions.

[piquark6046]

Also, updating redirection resources without updating whole program will be great.