feat: Docker Compose files in repos

compose.yaml, docker-compose.yml and their variants tracked by git are
listed under Repos, their services' environment variables as secrets,
named service.VAR.

- environment as a map or a list, and <<: *anchors shared between
  services; the secret patterns pick the keys, the rest hidden, with
  compose.secretPatterns for compose files' own.
- ${VAR}, $VAR, ${VAR:?…} and variables without a value are marked as
  references; docker-compose.example.yml and the like are hidden.
- Jasypt values decrypt with the service's JASYPT_ENCRYPTOR_PASSWORD.
- A blue Docker icon, themeable with composeColor.

internal/ui/icons/icons.go

@@ -12,6 +12,7 @@ type Set struct {
 	Encrypted  string // an encrypted file (SOPS)
 	PlainFile  string // a plain text secrets file (.env)
 	Spring     string // a Spring Boot config file
+	Compose    string // a Docker Compose file
 	Note       string // has a note (lazysecrets list)
 }
 
@@ -27,6 +28,7 @@ var NerdFont = Set{
 	Encrypted:  "\U000F033E", // md-lock
 	PlainFile:  "\U000F0214", // md-file
 	Spring:     "\U000F032A", // md-leaf
+	Compose:    "\U000F0868", // md-docker
 	Note:       "\U000F09ED",
 }