RURQ Module Updates

[TheGamingMousse]

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• [x] I have tested my code.

• [x] I have added my solution according to the steps here.

• [x] I have followed the code conventions mentioned here.

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• changed the module layout so I (think) it matches the module layout guidelines

• added an explanation for why the 2 BIT impl for range add range sum works

• added a somewhat brief explanation of how lazy segtrees work and some example code for horrible queries

• de-templified the main lazy segtree code for range update range sum and also added a template implementation

lmk if I should make the lazy segtree explanation a bit more in depth or if the module layout is wrong