CI: Run all tests when coverage is enabled ...

A recent change in the CI enabled coverage, however it did so on
the latest tags, meaning we were no longer running the other
tests (from the testsuite). This corrects it.

CLI: Slightly reduce memory allocations ...

By improving commandNames to only allocate once (the array call) instead
of many times (once per CommandGroup + join call),
as well as removing a call to commandNames and using a simple getter.

CLI: Simplify extractCommandNameArgument

Make 'Dependency.init' invalid and align Any/Invalid property ...

VersionRange has Invalid and Any while Dependency has invalid and any.
One has to go, and it's going to be Dependency's.
In addition, make sure that the 'init' state of Dependency is a known state.

Add a CI step to upload assets on release creation ...

We haven't had assets generated for releases since v1.29.0,
however some external code depend on them (dlang-community/setup-dlang, namely).
This will fix it and make it less likely to be forgotten in the future.

Adapt DependencyResolver to PackageName API

Add opEquals/opCmp to PackageName

Update configy to the latest HEAD

Merge pull request #2835 from ibuclaw/merge_stable ...

update version to v1.36.0

Merge remote-tracking branch 'upstream/stable' into merge_stable

update version to v1.36.0

Trivial: Slightly simplify PackageManager.store

Merge pull request #2833 from ibuclaw/merge_stable ...

merge stable

Merge remote-tracking branch 'upstream/stable' into merge_stable

update version to v1.36.0-rc.1

Build the tests and binary with -cov on POSIX ...

The CI was sending empty coverage reports because nothing
was being generated, as the variable was always false.
In the process, a bit of dead code was removed.

CI: Move single checks to Github, remove dead code ...

Remove support for very old frontend - we were not testing it anyways.
Move the useful checks to another job so they run once.

Remove internal mentions to Travis

Trivial: Fix #2774 - Color codes on windows terminal

Re-add CodeCov support

Trivial: Clean up temporary variable in Dub.fetch ...

And improve the message displayed to users.

Do not allow for removal of subpackages ...

Because it can mess up the system quite dramatically.

Improve unittest framework to have a virtual FS ...

This gets the unittest framework closer to the actual behavior,
and allows us to mock basic FS operations such as mkdir and writeFile.
Further improvements can be made to support more operations,
and to have package setup done before `TestDub` instantiation.

Adapt PackageManager.get[Best]Package to PackageName API ...

This paves the way to be able to automatically return subpackages.

Adapt loadSCMPackage to PackageName API

Trivial: Add 'in' on a parameter

Remove PackageName alias this to toString ...

The alias this was originally added to make the transition
less painful, however due to an overload resolution bug,
it makes it harder at the moment, as thje compiler prefers
calling the deprecated `string` overloads over the
`in PackageName` ones. So remove it and a few hacks along
the way.

Adapt dub.recipe.json to PackageName API

Adapt dub.recipe.sdl to PackageName API

Adapt PackageSuppliers to PackageName API ...

Since we recently did a semi-breaking change to PackageSuppliers,
now is the time to do it again (they will be in the same release).
Again the same logic applies: it's only a breaking change for those
inheriting from PackageSupplier, not those calling it,
and there is likely not a lot of people doing either out there.