implement custom node container for endlevellayer to resolve label overlap issues across the geode index

[RayDeeUx]

original code + approach by @Alphalaneous, based on code from https://github.com/Alphalaneous/NextKeyWhen.

this PR has been made to resolve overlap issues such as the screenshot below by @undefined06855, exacerbated by certain options from @absoIute's Mega Hack v9.x mod menu:

this change would affect at minimum the following mods (listed in alphabetical order):

• EndscreenTweaks (by @RayDeeUx)
• Mega Hack v9, Geode edition (by @absoIute)
• Next Key When? by @Alphalaneous
• Practice Attempts by @Uproxide

all four mod developers have been made aware of this proposal and agree to it.

as this pull request removes nodes from their intended node parents, it's best if the changes made from this PR were introduced to the geode index after Geode v5.x releases.

[RayDeeUx]

i did move the complete-message node to y pos 109 for all level types because:
(a) no one wanted y pos 147 for platformer levels let's be fr rn
(b) summary-container's nodes would be more important that avoiding the overlap is easier as a blanket treatment

complete-message is for editor levels, so this change won't affect the ypos of level completion messages for online levels

[RayDeeUx]

no one wanted [complete-message] y pos 147 for platformer levels let's be fr rn

for evidence of this: the end-text node is always at y position 95 regardless of level type/length, even though vanilla GD only shows one piece of information on EndLevelLayer