Store and share lighthouse configs, and write them to a swarm

[evoggy]

Follow-up to #38. Lighthouse configurations can now be stored like swarms: locally as <config>, or shared on the server cfcli signs in to (cfcli auth login) as <org>/<config>. Shared configurations work like shared swarms: revisions, sync on/off, pull/push, and copies on this computer when the server can't be reached.

lh config

• New commands: list, save (the Crazyflie's configuration), import, export (a file cfclient opens), delete, move, pull and push.
• display, write and check take a stored configuration by ID, a file (-i), or YAML piped in.
• With none of these, write lists all stored configurations to pick from, starting at the selected swarm's. Without a terminal it writes the selected swarm's. check always uses the selected swarm's.
• save and import onto an existing ID show what changes for each base station and ask first. delete and move list the swarms that fly in the configuration.
• name shows or changes the name a configuration is shown with; the ID stays the same.

Swarms

• A swarm can name the lighthouse config it flies in: lighthouse: in the swarm file, set with swarm config lh.
• A local swarm can only name a configuration on this computer, and a shared swarm only one in its organization, so everyone who uses the swarm can read it.
• swarm config lh without a configuration lists the ones the swarm can name. When not interactive, it shows the current one.
• swarm lh check compares every Crazyflie with that configuration and exits with 60 when some differ.
• swarm lh write writes it to the Crazyflies that don't have it, then reads it back. Crazyflies whose firmware supports too few base stations are refused before anything is written.
• swarm config add says how to give the swarm's configuration to the new Crazyflies.

Shared code

• Swarms and lighthouse configs share one implementation of local files and shared copies: modules/documents.rs, which replaces swarm/shared.rs.
• Copies of shared swarms move from synced/<server>/<org>/ to synced/<server>/swarms/<org>/. Existing copies are moved on first use.
• With sync on, lists now show the server's revision instead of the copy's. This also fixes shared swarm lists.

Docs: docs/lighthouse.md, docs/swarm.md, docs/settings.md, docs/auth.md and the README. Lighthouse config IDs complete in bash, zsh and PowerShell.

The second commit has the fixes from reviewing and testing the first. The third renames swarm config lighthouse to swarm config lh, like cfcli lh and swarm lh; the field in the swarm file stays lighthouse:. The fourth adds the lists to pick from and the rule for which configurations a swarm can name. The fifth drops a swarm's lighthouse config when swarm config move or import gives the swarm an ID that can't name it, and says so. The sixth adds lh config name to show or change a lighthouse config's name, like swarm config name.

Testing

• Unit tests pass.
• End to end against a local server, with two users in one organization. Tested:
  • storing, sharing and exporting configs; cflib reads the exported file
  • a change by the other user, sync off with pull/push and a push conflict
  • working without the server, with the change uploaded on reconnect
  • following a change of the organization's ID
  • swarm links, and the delete/move swarm lists
• On a Crazyflie over USB with firmware built for 4 base stations:
  • swarm lh check → write → check, and a second write skipped as up to date
  • refusal of a configuration with base station 5
  • lh config save, lh config write <id>
  • lh config check with a stored configuration, a file, a pipe and an empty stdin
• Not tested on hardware: a Crazyflie replacing a calibration right after swarm lh write (no base stations in view). That message is covered by a unit test.