Better installation methods

[elldritch]

Some ideas:

• Install script for curl | bash or other one-liner. We can probably take the script from jpillora/installer.
• npm install -g @fossa/cli
• brew install @fossa/cli

Some references:

• https://gist.github.com/steinwaywhw/a4cd19cda655b8249d908261a62687f8

[xizhao]

Currently, one liner using jpillora/installer

curl https://i.jpillora.com/fossas/fossa-cli! | bash && mv /usr/local/bin/fossa-cli /usr/local/bin/fossa

[elldritch]

We have an installer script now, but there are some improvements we can make:

• Automatically pull the latest stable version instead of a hardcoded version (probably by querying the Releases API)
• Figure out a way to validate the checksum on Mac OS (apparently sha256sum is not installed by default?)
• Install to a location other than /usr/bin to avoid requiring sudo permissions for most users (maybe install to .fossa, append it to the $PATH, and provide a .bashrc EXPORT PATH=$PATH:$HOME/.fossa line?)

[elldritch]

Our current installer satisfies these requirements pretty well.