Use doc_auto_cfg, logo and favicon for docs.rs

[mbrobbel]

Which issue does this PR close?

None.

Rationale for this change

1. Make it easier to discover required features for items in the arrow, parquet and object_store crates on docs.rs.
2. Add logos and favicon for arrow and parquet crates on docs.rs.

What changes are included in this PR?

• #![cfg_attr(docsrs, feature(doc_auto_cfg))] for all published crates (also the ones without features, to make this work when features are added in the feature).
• Set all-features = true in [package.metadata.docs.rs] for those crates to get docs for all items.
• Add logos for arrow (logo and favicon) and parquet (logo/favicon) on docs.rs.
• Removed src/lib.rs from [lib] sections (this is the default value), and removed some empty [*-dependencies] sections in Cargo.toml files.

To test this locally (requires nightly rust + cargo-docs-rs):

rustup toolchain install nightly
cargo install --locked cargo-docs-rs
cargo +nightly docs-rs -p <crate>

Are there any user-facing changes?

Users will now see required features on docs.rs.

[alamb]

Thank you so much @mbrobbel -- this is super useful

I tested this PR out locally and it looks really nice