Commands to install avalanchego & subnetevm w/out starting a network or subnet

[feuGeneA]

We maintain bash scripts to install avalanchego and subnet-evm in our dev environments:

• subnet-evm has one for avalanchego: https://github.com/ava-labs/subnet-evm/blob/master/scripts/install_avalanchego_release.sh
• teleporter has one for avalanchego and one for subnetevm

It would be nice if we could use the CLI to install these binaries, and dispense with the bulk of those bash scripts.

I tried to change the teleporter development environment to cut out these bash scripts and use what gets installed by the CLI, in this PR.

However, the best way I could find to do it was to start a network with a specific avalanchego-version, and then refer to the binary in ~/.avalanche-cli/bin/avalanchego/..., and start a subnet with a specific subnetevm version, and again refer to ~/.avalanche-cli/bin, in bin/subnet-evm.

However, that approach has the down side of deleting/overwriting any configuration that was already set up.

It would be nice if the CLI could be invoked to do the installation it's already doing, just without starting up networks using those installed binaries.

Please consider adding commands like avalanche install avalanchego --version v9.8.7 and avalanche install subnet-evm --version v9.8.7.