RTC-520 add notifications: PeerAdded, PeerDeleted

[Rados13]

Acknowledging the stipulations set forth:

• [x] I hereby confirm that a Pull Request involving updates to the Software Development Kit (SDK) has been smoothly merged, currently awaits processing, or is otherwise deemed unnecessary in this context.
• [x] I also affirm that another Pull Request, specifically addressing updates to the documentation body (commonly referred to as 'docs'), has either been successfully incorporated, is in the process of review, or is considered superfluous under the prevailing circumstances.

Blocked by: https://github.com/jellyfish-dev/protos/pull/18 Elixir SDK PR Python SDK PR

[codecov[bot]]

Codecov Report

Merging #183 (95c4ce8) into main (69e3a61) will increase coverage by 0.06%. The diff coverage is 84.61%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #183 +/- ## ========================================== + Coverage 86.85% 86.91% +0.06% ========================================== Files 74 74 Lines 1491 1498 +7 ========================================== + Hits 1295 1302 +7 Misses 196 196 ``` | [Files](https://app.codecov.io/gh/jellyfish-dev/jellyfish/pull/183?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=jellyfish-dev) | Coverage Δ | | |---|---|---| | [lib/jellyfish/event.ex](https://app.codecov.io/gh/jellyfish-dev/jellyfish/pull/183?src=pr&el=tree&filepath=lib%2Fjellyfish%2Fevent.ex&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=jellyfish-dev#diff-bGliL2plbGx5ZmlzaC9ldmVudC5leA==) | `87.87% <100.00%> (+0.78%)` | :arrow_up: | | [lib/jellyfish/room.ex](https://app.codecov.io/gh/jellyfish-dev/jellyfish/pull/183?src=pr&el=tree&filepath=lib%2Fjellyfish%2Froom.ex&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=jellyfish-dev#diff-bGliL2plbGx5ZmlzaC9yb29tLmV4) | `80.27% <100.00%> (-0.14%)` | :arrow_down: | | [lib/jellyfish/room/state.ex](https://app.codecov.io/gh/jellyfish-dev/jellyfish/pull/183?src=pr&el=tree&filepath=lib%2Fjellyfish%2Froom%2Fstate.ex&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=jellyfish-dev#diff-bGliL2plbGx5ZmlzaC9yb29tL3N0YXRlLmV4) | `87.89% <80.00%> (+0.48%)` | :arrow_up: | ------ [Continue to review full report in Codecov by Sentry](https://app.codecov.io/gh/jellyfish-dev/jellyfish/pull/183?dropdown=coverage&src=pr&el=continue&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=jellyfish-dev). > **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=jellyfish-dev) > `Δ = absolute (impact)`, `ø = not affected`, `? = missing data` > Powered by [Codecov](https://app.codecov.io/gh/jellyfish-dev/jellyfish/pull/183?dropdown=coverage&src=pr&el=footer&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=jellyfish-dev). Last update [69e3a61...95c4ce8](https://app.codecov.io/gh/jellyfish-dev/jellyfish/pull/183?dropdown=coverage&src=pr&el=lastupdated&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=jellyfish-dev). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=jellyfish-dev).