treewide: move all modules into new submodule to fix relative imports

python, why are you like this?

main.py

@@ -1,7 +1,7 @@
 from PyQt5 import QtWidgets
 import sys
 
-from astrodatagui.AstrodataGUI import AstrodataGUI
+from main.astrodatagui.AstrodataGUI import AstrodataGUI
 
 app = QtWidgets.QApplication(sys.argv)
 window = AstrodataGUI()

main/astrodatagui/astrodatagui.ui

@@ -251,7 +251,7 @@
   <customwidget>
    <class>FlaredetectorWidget</class>
    <extends>QWidget</extends>
-   <header>astrodatagui.ui.FlaredetectorWidget</header>
+   <header>main.astrodatagui.ui.FlaredetectorWidget</header>
    <container>1</container>
   </customwidget>
  </customwidgets>