Support for remote content repository where all contents and
manifests are fetched over HTTP(S) instead of locally
manipulating blob storage
* server: implement content and manifest access APIs
* apiclient: moved Kopia API client to separate package
* content: exposed content.ValidatePrefix()
* manifest: added JSON serialization attributes to EntryMetadata
* repo: changed repo.Open() to return Repository instead of *DirectRepository
* repo: added apiServerRepository
* cli: added 'kopia repository connect server'
This sets up repository connection via the API server instead of
directly-manipulated storage.
* server: add support for specifying a list of usernames/password via --htpasswd-file
* tests: added API server repository E2E test
* server: only return manifests (policies and snapshots) belonging to authenticated user
Those will make it possible to securely host 'kopia server' embedded
in a desktop app that runs in the background and can access UI.
- added support for using and generating TLS certificates
- added /api/v1/shutdown API to remotely trigger server shutdown
- added support for automatically shutting down server if no requests
arrive in certain amount of time
- added support for generating and printing random password to STDERR
TLS supports 3 modes:
1. serve TLS using externally-provided cert/key PEM files
2. generate & write PEM files, then serve TLS using them
3. generate and use emphemeral cert/key (prints SHA256 fingerprint)
