Create a function to allow the "merging" of multiple auths

[Badgerati]

Describe the Change

This is from #575.

Could it be possible to have some Merge-PodeAuth function, which would allow the merging of multiple auth methods?

For example:

Merge-PodeAuth -Name -Auths[] <-All> <-One>

This will return a "merged" auth type usable on Routes, and you can either have All auths needed to pass, or just One to pass.

[Badgerati]

I've extended this to also cover the new Access methods as well, and tweaked the way they work from #992 slightly.

There is now two new Merge-PodeAuth and Merge-PodeAuthAccess functions, which will let you build more advanced authentication and authorization strategies - and yes you can merge and merged Auth method with another Auth method 😄

I'm also making Test-PodeAuth and Test-PodeAuthExists public, for further advanced/custom scenarios where you want to run the authentication validation manually.

[Badgerati]

I have overhauled the core authentication validation logic quite a bit. In my initial tests so far there haven't been any breaking changes, and all existing auth methods still work - but it will need more testing to make sure.

[Badgerati]

All testing seems good 😄 Just need to update the docs.