Deprecate contract install in favor of contract upload.

[fnando]

What

Deprecate contract install in favor of contract upload.

$ stellar contract install --wasm target/wasm32-unknown-unknown/release/hello_world.wasm
⚠️ `stellar contract install` has been deprecated in favor of `stellar contract upload`
ℹ️ Skipping install because wasm already installed
89123eaa2902ec32e26db0141e2d0247e5e00846489f4d8b17d597a85466e863

$ stellar contract upload --wasm target/wasm32-unknown-unknown/release/hello_world.wasm
ℹ️ Skipping install because wasm already installed
89123eaa2902ec32e26db0141e2d0247e5e00846489f4d8b17d597a85466e863

Why

Close #1621.

Known limitations

N/A

[willemneal]

This adds an extra entry in the docs which is a little confusing. Though I agree there should be a way to determine if install was used. So 🤷