feat(ci): additional code/deps/security checks (#37)

To improve `CI` quality the following checks were added:

* compile warnings
* deprecated dependencies
* insecure dependencies
* unused dependencies
* code vulnerabilities

Also, to improve `CI` execution time, dependencies checks and lining were separated from the test pipeline.

Last, but not least, to make local development easier a `Dockerfile` was created to contain any system dependencies, and targets to handle database creation and migration were added.

Reviewed-on: #37

Dockerfile

@@ -0,0 +1,10 @@
+FROM elixir:1.15.7-slim AS builder
+
+RUN apt-get update \
+  && apt-get -y install make
+
+WORKDIR /opt/app
+COPY ./mix.exs ./
+COPY ./mix.lock ./
+RUN mix do local.hex --force, local.rebar --force \
+  && mix do deps.get, deps.compile