feat: consistent flags and environment variables (#5549)

- In the root command, all flags are now correctly available as environmental variables, except for `--config` flag. This was already supposed to be the case, but due to bugs in the implementation it didn't work properly.
- All configuration options (unless I missed something) that are available as flags should now properly update the configuration when using the `config init` and `config set` commands.
- Flag names are now consistently in the lowerCamelCase format. All flags that were in a different format have been updated in a backwards compatible way. For a transitionary period of at least 6 months, both will work:
  - `--dir-mode` --> `--dirMode`
  - `--hide-login-button` --> `--hideLoginButton`
  - `--create-user-dir` --> `--createUserDir`
  - `--minimum-password-length` --> `--minimumPasswordLength`
  - `--socket-perm` --> `--socketPerm`
  - `--disable-thumbnails` --> `--disableThumbnails`
  - `--disable-preview-resize` --> `--disablePreviewResize`
  - `--disable-exec` --> `--disableExec`
  - `--disable-type-detection-by-header` --> `--disableTypeDetectionByHeader`
  - `--img-processors` --> `--imageProcessors`
  - `--cache-dir` --> `--cacheDir`
  - `--token-expiration-time` --> `--tokenExpirationTime`
  - `--baseurl` --> `--baseURL`

cmd/users_import.go

@@ -26,6 +26,7 @@ installation. For that, just don't place their ID on the files
 list or set it to 0.`,
 	Args: jsonYamlArg,
 	RunE: python(func(cmd *cobra.Command, args []string, d *pythonData) error {
+		flags := cmd.Flags()
 		fd, err := os.Open(args[0])
 		if err != nil {
 			return err
@@ -45,7 +46,7 @@ list or set it to 0.`,
 			}
 		}
 
-		replace, err := getBool(cmd.Flags(), "replace")
+		replace, err := flags.GetBool("replace")
 		if err != nil {
 			return err
 		}
@@ -69,7 +70,7 @@ list or set it to 0.`,
 			}
 		}
 
-		overwrite, err := getBool(cmd.Flags(), "overwrite")
+		overwrite, err := flags.GetBool("overwrite")
 		if err != nil {
 			return err
 		}