Phobos 3 Development is Open!

[Adam Wilson]

The first PR for Phobos 3 has been merged into the Phobos repo!

Now, to be clear, this is mostly a housekeeping PR that paves the 
way for further work and there isn't actually anything useful in 
it yet. We've setup the basic structure, DUB build/test config, 
and copied over the modules that don't have any `std` imports. 
The next project will be to (slowly) audit each file for any 
trace of auto-decoding. No module can be added to V3 without 
first being cleared of auto-decoding.

With this comes a few changes in the development process for 
Phobos. The first of which is that all changes to Phobos will now 
need to be cross-applied to both libraries. We have kept V3 in 
the same repo as V2 to make this process easier, but you will 
need to check the V3 directory (tentatively labeled `lib`) to see 
if the V2 file you're modifying is included in V3 yet, and if it 
is, please include your change in corresponding V3 file as well. 
This will be enforced during the review process. If you are 
unsure, you can ping me on GitHub as `@LightBender` in your PR 
and I'll take a look. As we progress, I am sure that the other 
reviewers will become familiar with the state of the V3 code-base.

Note that this process will continue for the indefinite future as 
we intended to maintain V2 alongside V3+. While the exact level 
of support that V2 will receive once V3 is launched hasn't been 
fulled resolved, at a minimum, it must remain in a buildable 
state indefinitely.

Another note is that I do have a day job, so I will only be 
working on V3 in my spare time, as such, any help with the 
auto-decoding audit would be immensely appreciated as that will 
significantly speed up the time to completion and let us start 
focusing on the projects we all want to see happen in Phobos.

If you have any V3 specific questions or comments you can join 
the discussion that's happening in this GitHub repo: 
https://github.com/LightBender/PhobosV3-Design
Or, you can ask on the Forums and in the Discord and I'll do my 
best to keep up with the updates in those places.

Finally, I would like to thank everybody who has contributed to 
the design of V3 already  (there are too many to list, you know 
who you are), you've been a wonderful help as we start this 
journey. Thanks to your efforts the future of Phobos is looking 
very bright!