feat: login and register connects to overview

.gitignore

...orschen/src/main/java/unipotsdam/gf/GFDatabaseConfig.java

.../java/unipotsdam/gf/core/database/mysql/MysqlConnect.java

...ipotsdam/gf/core/management/user/servlets/CreateUser.java

...ipotsdam/gf/core/management/user/servlets/UserExists.java

...dam/gf/core/management/user/servlets/UserHttpServlet.java

...en/src/main/webapp/assets/bootstrap/css/bootstrap.min.css

...p/assets/bootstrap/fonts/glyphicons-halflings-regular.eot

...p/assets/bootstrap/fonts/glyphicons-halflings-regular.svg

...p/assets/bootstrap/fonts/glyphicons-halflings-regular.ttf

.../assets/bootstrap/fonts/glyphicons-halflings-regular.woff

...assets/bootstrap/fonts/glyphicons-halflings-regular.woff2

...chen/src/main/webapp/assets/bootstrap/js/bootstrap.min.js

...orschen/src/main/webapp/assets/css/Contact-Form-Clean.css

...webapp/assets/css/Customizable-Carousel-swipe-enabled.css

...mforschen/src/main/webapp/assets/css/Login-Form-Clean.css

...mforschen/src/main/webapp/assets/css/MUSA_panel-table.css

...forschen/src/main/webapp/assets/css/MUSA_panel-table1.css

...en/src/main/webapp/assets/css/Navigation-with-Button1.css

...insamforschen/src/main/webapp/assets/css/Sidebar-Menu.css