Completed installation and quickstart sections

[HrikB]

This PR completes the installation and quickstart sections of the book.

Closes INT-2881

[linear]

INT-2881 Install and quickstart

can mostly copy https://docs.succinct.xyz/docs/getting-started/install

but ours is simpler right now:

Install cargo openvm from source:

1. either clone the repo and cargo install --force --path . from crates/cli or
2. cargo install --git (I've never tried this and it might only work with public repo)

We don't need to install any special toolchains, just nightly-2024-10-30

For quickstart, add example of writing fibonacci program, starting from cargo init , add openvm = { …, features = ["std"] } and include the guest program code. We don't need the no_main, no_std stuff for quickstart since std works. Copy the rest of fibonacci from the benchmark, in particular use read.

Give the commands on how to run it using cargo openvm run or cargo openvm bench (hopefully that works).

• we have --input here, will need to figure out how to use it

[jonathanpwang]

updated for latest cli