feat: setup thymeleaf

• remove the frontend project from gradle
• remove the angular filter
• create a basic layout and home page using thymeleaf

.idea/compiler.xml

-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="CompilerConfiguration">
-    <annotationProcessing>
-      <profile name="Gradle Imported" enabled="true">
-        <outputRelativeToContentRoot value="true" />
-        <processorPath useClasspath="false">
-          <entry name="$USER_HOME$/.gradle/caches/modules-2/files-2.1/org.springframework.boot/spring-boot-configuration-processor/2.1.2.RELEASE/db9671c321defb942a6700fae8a7700a137a25e/spring-boot-configuration-processor-2.1.2.RELEASE.jar" />
-        </processorPath>
-        <module name="faidare.backend.main" />
-      </profile>
-    </annotationProcessing>
-    <bytecodeTargetLevel target="1.8" />
-  </component>
-</project>
\ No newline at end of file