Update bin/ci script to run credo & fix warnings

[zberkom]

Software Design
┃
┃ [D] → Found a TODO tag in a comment: # TODO: Issue #83 - intermittent issue
┃ with duplicate content rows
┃ lib/thesis/stores/ecto_store.ex:65 #(Thesis.EctoStore.page_contents)
┃ [D] → Found a TODO tag in a comment: # TODO: Update to String.trim when we
┃ only support Elixir >= 1.3 in the future.
┃ lib/thesis/render.ex:64 #(Thesis.Render.wrapper_attributes)
┃ [D] → Found a TODO tag in a comment: # TODO: Refactor into nicer pipeline
┃ lib/thesis/render.ex:63 #(Thesis.Render.wrapper_attributes)
┃ [D] → Found a TODO tag in a comment: # TODO: better way to infer app path?
┃ lib/mix/tasks/thesis.install.ex:52 #(Mix.Tasks.Thesis.Install.thesis_templates)

Code Readability
┃
┃ [R] ↓ There should be no more than 1 consecutive blank lines.
┃ lib/thesis/api_controller.ex:94 #(Thesis.ApiController.put_unauthorized)
┃ [R] ↓ Line is too long (max is 120, was 133).
┃ lib/mix/utils.ex:60:121 #(Mix.Thesis.Utils.copy_to_target)
┃ [R] ↓ There should be no more than 1 consecutive blank lines.
┃ lib/thesis/utilities.ex:6 #(Thesis.Utilities)
┃ [R] ↓ There should be no trailing white-space at the end of a line.
┃ lib/thesis/uploaders/s3_uploader.ex:9:1 #(Thesis.S3Uploader.upload)
┃ [R] ↓ There should be no more than 1 consecutive blank lines.
┃ lib/thesis/stores/store.ex:45 #(Thesis.Store)

Refactoring opportunities
┃
┃ [F] → Pipe chain should start with a raw value.
┃ lib/mix/tasks/thesis.install.ex:109 #(Mix.Tasks.Thesis.Install.insert_in)
┃ [F] → Pipe chain should start with a raw value.
┃ lib/thesis/utilities.ex:20 #(Thesis.Utilities.parameterize)
┃ [F] ↓ Double boolean negation found.
┃ lib/thesis/view.ex:221 #(Thesis.View.editable?)

Consistency
┃
┃ [C] ↗ There is no whitespace around parentheses/brackets most of the time, but
┃ here there is.
┃ lib/thesis/stores/ecto_store.ex:62 #(Thesis.EctoStore.page_contents)