Rework ImageBanner Support

Refactor several aspects of the ImageBanner:

- Extract a few new classes and methods from the previous code
- Directly encode ANSI rather than using `${}` properties
- Rework the scaling algorithm to prefer a fixed width
- Allow ImageBanner and TextBanner to be used together
- Rename several of the `banner.image` properties
- Add support for a left hand margin
- Add property meta-data

See gh-4647

spring-boot-samples/spring-boot-sample-simple/src/main/resources/application.properties

@@ -1 +1 @@
-name: Phil
+name: Phil

spring-boot-samples/spring-boot-sample-simple/src/main/resources/banner.txt

@@ -0,0 +1 @@
+${Ansi.GREEN} :: Sample application build with Spring Boot${spring-boot.formatted-version} ::${Ansi.DEFAULT}