Renames frame crate to polkadot-sdk-frame

[gupnik]

Step in #3155

Needed for paritytech/eng-automation#6

This PR renames frame crate to polkadot-sdk-frame as frame is not available on crates.io

[xlc]

if we are going to do a rename, can we rename everything? e.g. all the staging- creates

[gupnik]

if we are going to do a rename, can we rename everything? e.g. all the staging- creates

I will keep this one confined to the frame crate but please open an issue for the others that you would like to be renamed.

[liamaharon]

if we are going to do a rename, can we rename everything? e.g. all the staging- creates

I think for the ones with the staging- prefix we are actually in the process of recovering the rights to the original crate name. I don't think we should add to confusion by creating a new intermediate one.

[kianenigma]

I would say just import the crate with package = "poladkto-sdk-frame" and then the code more or less remain the same everywhere.

wdyt @ggwpez @liamaharon?

Similarly, in all template codes, we should still retain frame::prelude::* etc.

[kianenigma]

I agree with the direction of allowing polkadot-sdk-frame, and letting it be re-imported as frame. need better tests to ensure exactly these two scenarios are supported