Add extension method to chain FileLifecycleHooks together

[EamonHetherton]

Allows composing of FileLifecycleHooks e.g. Add FileHeaders and GZip the logs, or compress then encrypt.

[nblumhardt]

Looks good; since FileLifecycleHooks is defined in this assembly, it could be implemented as an instance method rather than an extension?

Since there's a strong concept of ordering between chained hooks, perhaps we could use a name like Then() or something along those lines?

var hooks = new GZipHooks().Then(new HeaderWriter("File Header"));

[EamonHetherton]

yeah, agree on both. Was never happy with "ChainTo" :)

And it is an extension as it started life in my own project, but makes sense as an instance.

will update...

[nblumhardt]

LGTM! 👍