Use shell:start_interactive to start shell if available

[garazdawi]

In Erlang/OTP 26 there is support for starting a shell session
from an escript instead of using the hack that is currently used.
So we make sure to use that method if possible.

See erlang/otp#6144 for details on the new shell

Note: At the moment rebar3 is started with "-noshell" which is the default for escripts. In 26 it will also be possible to start an escript in "-noinput" and then change to "-noshell" or start a shell session depending on what the application wants to do. I don't know if rebar3 should change to "-noinput", but I thought I would just mention it so that you know that the possibility exists.

[tsloughter]

I guess @ferd might be the one to ask since he wrote the original, but Is all the logger removal, old shell fallback, ... stuff handled by the new start_interactive, or otherwise not needed?

[garazdawi]

As start_interactive works right now the oldshell fallback is needed. Though I think that it might be better to improve start_interactive than to handle that in rebar3.

I don't think that the logger workaround is needed.

[ferd]

This is going to simplify a lot of things and when we can finally assume this to be the norm in ~2 years it's going to finally kill some of the hackiest code I've ever written.

A very welcome change!

[garazdawi]

Fyi I've opened a new pr (erlang/otp#6279) that make shell:start_interactive work with "oldshell" and also adds -remsh support into "oldshell" so that we finally get rid of that problem.