fix(search): provide graceful warning when a registry is offline

[zeroshade]

fixes #295

Changes dbc search to succeed with a warning if any of the registries still succeed and return a list of drivers while one or more fail.

If there's an error but no drivers at all then we still fail entirely.

[ianmcook]

I didn't realize it when I opened the issue, but apparently dbc install and dbc add also fail in this case. Can you solve that too?

[ianmcook]

If dbc install or dbc add finds the driver the user requests in the public registry, it shouldn't print a warning, it should just succeed.

[ianmcook]

Edge case that this doesn't handle well: if BOTH registries are unreachable, it prints both a warning and an error:

[zeroshade]

@ianmcook @amoeba updated based on the comments, please check again

[ianmcook]

Looks like dbc sync suffers the same issue 🙃
Can you fix that too please @zeroshade ?

[ianmcook]

And dbc info and dbc docs, too!

[zeroshade]

@ianmcook I've updated all the subcommands appropriately. we should have all the scenarios covered now

[ianmcook]

Seems good now! Thanks @zeroshade