Add track_content option to allow hashing of include_dependencys

[fatteneder]

Continuation of #49866.
Fixes #52462

So far any include_dependency was tracked by mtime.
A package using include_dependency can't be relocated without recompilation if the dependency also needs to be relocated.

With include_dependency(path, track_content=true) the tracking works like for include,
i.e. recompilation is only triggered when the file's content changes.
In case path is a directory we use the string join(readdir(path)) as content.

[fatteneder]

Need to add a Julia compat note to docs.

[fatteneder]

After rebasing there is now a test failure that seems related to #53103.
Need to look into that.