feat!: restructure erstie guide, expand

Expanded the erstie guide massively (added guide for each semester),
restructured to new URLs, added summaries details

summaries/semester3.md

@@ -1 +1,19 @@
 # Semester 3
+## Theoretical Computer Science
+The main summary is pretty much a short script for the course, whereas my compact summary is focused teaching you the proof techniques, etc.
+- [Summary (DE)](https://github.com/janishutz/eth-summaries/blob/main/semester3/ti/main/ti-summary.pdf) Author: Janis Hutz
+- [Compact Summary (EN)](https://github.com/janishutz/eth-summaries/blob/main/semester3/ti/compact/ti-compact.pdf) Author: Janis Hutz
+- [Cheatsheet (DE)](https://github.com/janishutz/eth-summaries/blob/main/semester3/ti/cheatsheet/ti-cheatsheet.pdf) Author: Robin Bacher
+
+## Analysis II
+My own cheat sheet is not all that great in terms of layout, as it was still written with my (woefully inept for compact Cheat Sheets) old helper files
+- [Cheat-Sheet (EN)](https://github.com/janishutz/eth-summaries/blob/main/semester3/analysis-ii/cheat-sheet-jh/analysis-ii-cheat-sheet.pdf) Author: Janis Hutz
+- [Cheat-Sheet (EN)](https://github.com/janishutz/eth-summaries/blob/main/semester3/analysis-ii/cheat-sheet-rb/main.pdf) Author: Robin Bacher
+
+## Numerical Methods for Computer Science
+The NumCS summary isn't even really a summary anymore, it is pretty much a full replacement for the script due to the poor quality of the script in many cases.
+- [Summary (DE)](https://github.com/janishutz/eth-summaries/blob/main/semester3/numcs/numcs-summary.pdf) Authors: Robin Bacher, Janis Hutz
+
+## Systems Programming and Computer Architecture
+This summary also contains a very broad overview of the content of the course, covering almost every aspect.
+- [Summary (EN)](https://github.com/janishutz/eth-summaries/blob/main/semester3/spca/spca-summary.pdf) Authors: Robin Bacher, Janis Hutz