fix(balancer): miscellaneous improvements before resync (#104)

* fix(balancer): ignore self balance change

Euler pool emit a balance change for the pool itself. We don't want to have it because it's an unknown token from Tycho's perspective.

example: https://etherscan.io/tx/0x4a9ea683052afefdae3d189862868c3a7dc8f431d1d9828b6bfd9451a8816426#eventlog#338

* refactor(balancer): rename balancer module to balancer-v2

* ci: make clippy happy

---------

Co-authored-by: zizou <111426680+flopell@users.noreply.github.com>

substreams/ethereum-balancer-v2/abi/README.md

@@ -0,0 +1,22 @@
+# ABIs
+
+`get_abis.py` is a simple python script using the etherscan API (free plan) to gather ABIs for all of the contracts we are tracking!
+
+We then can define all of the abis via `substreams_ethereum::Abigen::new` in our `build.rs`.
+
+## Recommendation
+
+It would be apt to convert (maybe through copilot) the python code into the `build.rs` file and then automate the `Abigen` functionality.
+
+## Usage
+
+Requires `python 3.8+`,
+
+```bash
+cd abi
+python get_abis.py
+```
+
+This will populate the files in the `abi` folder.
+
+When the `build.rs` file runs (when `rust-analyzer` activates or `cargo build` is manually ran), Abigen will generate new rust src files from the abis in the `src/abi` folder.