Make keys generate to no longer fund

[Ifropc]

What

Previously, --fund flag was added, and funding by default gave a warning.
In this PR -no-fund flag was removed, and default behavior flipped to no longer fund

Why

Closing #1407

Known limitations

Depends on #1888

[fnando]

lgtm!

[tupui]

Oh, no deprecation warning? I was personally relying on auto funding for my tests 😅

[fnando]

@tupui this command was already outputing a deprecation message on v22, and will be removed on v23.

$ stellar --version
stellar 22.3.0 (3a00de5e6c579479e943f5914f2fcfaca8426c8c)
stellar-xdr 22.1.0 (e13922970800d95b523413018b2279df42df3442)
xdr curr (529d5176f24c73eeccfa5eba481d4e89c19b1181)

 $ stellar keys generate foo
⚠️ Behavior of `generate` will change in the future, and it will no longer fund by default. If you want to fund please provide `--fund` flag. If you don't need to fund your keys in the future, ignore this warning. It can be suppressed with -q flag.
✅ Key saved with alias foo in "/private/tmp/test/.stellar/identity/foo.toml"
✅ Account KeyName("foo") funded on "Test SDF Network ; September 2015"

You can fund the account by using stellar keys generate foo --fund from now on.

[tupui]

Thanks, I will pay more attention to the command outputs 👍 It was missing from the release notes of v22 which I read. That's how I came across this PR.

[EDIT] I see Add warning on no fund flag but this is really not clear, especially without a deprecated section.

[fnando]

@tupui good call! I'll let the team know so we have better documentation on deprecations and removals using the release page.

[tupui]

Thank you 🙇