Add preferred default release profile settings

[ascjones]

Rel #40, use-ink/ink#448

If any of the following [profile.release] settings are missing, then they are added with the following preferred defaults:

[profile.release]
panic = "abort"
lto = true
opt-level = "z"
overflow-checks = true
codegen-units = 1

Any of the above that are manually specified are not overwritten. This allows manual control over e.g. opt-level where in some cases opt-level = 3 might result in a smaller binary size.

Template changes:

• Remove [profile.release] section
• Use scale-info from crates.io instead of type-metadata (reverted: requires ink! 3 release)

[Robbepop]

All in all LGTM, some renamings wouldn't hurt though.
Also really nice feature!

[Robbepop]

Would it be much worse to have FatLto, ThinLto and Off as variants? Kind of dislike the Bool here.

[ascjones]

See what you think of the explicit variants

[Robbepop]

LGTM