chore(repo-size): drop large-sized commits from history

## Issue summary

- As a new developer, cloning the repository takes ~30s and the repository then takes 315MB of disk space. I think these two could be reduced by dropping large commits containing unnecessary/committed by mistake files
- Low priority, can be done post v1.0.0
- We can either drop the commits or amend them to not contain those large files (such as `cmd/gossamer/.DS_Store` in d096d44912365942d66f46fe539f4328cb44e7e3)

You can use this command on a GNU system (e.g. debian)

```sh
git rev-list --objects --all |
git cat-file --batch-check='%(objecttype) %(objectname) %(objectsize) %(rest)' |
sed -n 's/^blob //p' |
sort --numeric-sort --key=2 |
cut -c 1-12,41- |
$(command -v gnumfmt || echo numfmt) --field=2 --to=iec-i --suffix=B --padding=7 --round=nearest
```

The top largest files committed are (2021-10-31):

```
db3b2dee8066 1.1MiB polkadot_runtime.wasm
5aecd1af4605 1.4MiB docs/docs/assets/img/block_production.png
9c3aae112077 1.5MiB test_wasm.wasm
43f456c48e2e 2.1MiB tests/utils/genesis_oneauth.json
7bbe85fc589a 2.1MiB tests/utils/genesis_threeauths.json
bd96b3d4364c 2.1MiB chain/gssmr/genesis-raw.json
e2c7a898fc60 2.1MiB chain/gssmr/genesis-raw.json
2ef5058c49a2 2.1MiB chain/gssmr/genesis.json
df519aea3695 2.1MiB chain/gssmr/genesis.json
da74aa763af7 2.1MiB tests/utils/genesis_sixauths.json
91d569948a89 2.1MiB chain/gssmr/genesis.json
19afa05715ea 2.1MiB chain/gssmr/genesis.json
16b08a02b3e2 2.1MiB chain/gssmr/genesis.json
1e9ebe1b03b0 2.4MiB tests/polkadotjs_test/test/node_runtime.compact.wasm
7ba00a3febfc 2.7MiB chain/ksmcc/genesis-raw.json
db4beb2420e2 2.7MiB chain/ksmcc/genesis-raw.json
2b44f2c19e13 2.7MiB chain/ksmcc/genesis-raw.json
d12786ec0705 2.7MiB config/ksmcc3.json
48b2e9992113 2.7MiB node/ksmcc/genesis.json
18b1c99127a5 2.7MiB chain/ksmcc/genesis-raw.json
e391afc193b0 2.7MiB chain/kusama/genesis.json
34ae8cd0ea27 2.8MiB lib/runtime/test_data/kusama/block3783.out
ac2d8490c220 2.8MiB lib/runtime/test_data/block3875.out
b1bb26c42803 3.7MiB test_genesis.json
754f6e2f9bcc 3.9MiB chain/polkadot/genesis.json
8cd854d94373 4.8MiB tests/utils/genesis_threeauths.json
e1d6c1d98c9e 4.8MiB chain/gssmr/genesis-raw.json
fc40d7e39e20 4.8MiB chain/gssmr/genesis-raw.json
2dded8903b07 4.8MiB chain/gssmr/genesis.json
e289511a2abb 4.8MiB chain/gssmr/genesis.json
a9453d0afc56 4.8MiB chain/gssmr/genesis.json
352500a206bb 4.8MiB chain/gssmr/genesis.json
5dce23e90b62 4.8MiB chain/gssmr/genesis-spec.json
70fa2fcce723 4.8MiB chain/gssmr/genesis-raw.json
62e90c2a41ef 4.8MiB chain/gssmr/genesis-raw.json
3606dafd448b 4.8MiB chain/gssmr/genesis-raw.json
93f5abc30576 4.8MiB chain/gssmr/genesis-raw.json
ead64112edf0 4.8MiB chain/gssmr/genesis-raw.json
92421695da39 4.8MiB chain/dev/genesis-spec.json
e8795c482918 4.8MiB chain/gssmr/genesis-raw.json
2e6f157d9048 4.8MiB chain/gssmr/genesis.json
080619e282b3 4.8MiB chain/gssmr/genesis.json
a5a8ca24e5f9 4.8MiB chain/dev/genesis.json
6b76f85b457e 4.8MiB chain/dev/genesis.json
0419fd6a2897 4.8MiB chain/dev/genesis.json
d8ea4d725799 5.1MiB chain/dev/genesis-spec.json
b73752e61bf5 5.1MiB chain/dev/genesis-spec.json
23f3264a8049 5.1MiB chain/gssmr/genesis-spec.json
279f93547014 5.1MiB chain/gssmr/genesis-spec.json
4c7e4917917e 5.1MiB chain/gssmr/genesis.json
5ed1980b1240 5.1MiB chain/gssmr/genesis.json
49b24868c476 5.1MiB chain/gssmr/genesis.json
662d4172f310 5.1MiB chain/dev/genesis-spec.json
06a643c235db 5.1MiB chain/dev/genesis.json
6cb8c7615ff5 5.1MiB chain/dev/genesis.json
ca9f1b59e591 5.1MiB chain/gssmr/genesis-spec.json
d5145d0ee2f3 5.1MiB chain/gssmr/genesis.json
6a34fa92119b 5.1MiB chain/gssmr/genesis.json
36cf8f164c72 5.3MiB chain/polkadot/genesis-raw.json
d26d66badd37 5.3MiB chain/polkadot/genesis.json
1e7e304124f5 8.9MiB tests/data/db/000000.vlog
54d02f55f44a 9.2MiB chain/polkadot/genesis.json
079ef1515810 9.7MiB bin/subkey
4d09cc391810 15MiB lib/runtime/test_data/kusama/block1377830.out
2418d2b70cd8 19MiB lib/runtime/wasmer/__debug_bin
6a9d1b105e60 21MiB lib/runtime/test_data/kusama/block901441.out
5828ef5a23de 29MiB lib/runtime/test_data/polkadot/block1089327.json
4dcf69cbfa06 32MiB lib/runtime/test_data/kusama/block1482002.out
9cee4793aab6 53MiB cmd/gossamer/gossamer
f926eb66b151 75MiB node_runtime.wat
```