replace platform visible checkbox with switch

fixes #40

- add podcast sidebar navigation
- add podcast dashboard with latest episodes
- add pagination to podcast episodes
- add components helper to reuse ui components (button, data_table, etc.)
- enhance podcast and episode forms by splitting them into form sections
- add hint tooltips to podcast and episode forms
- transform radio inputs as buttons for better ux
- replace explicit field by parental_advisory
- replace author field by publisher
- add podcasts_categories table to set multiple categories
- use choices.js to enhance multiselect fields
- update Language files
- update js dependencies to latest versions

closes #31, #9

- resize uploaded image to thumbnail, medium, large, feed, and id3 formats
- set image url formats where adapted in views
- set format sizes and extensions in Images config file for customization
- add validation for image uploads: `min_dims` and `is_image_squared`
- update codeigniter4 and myth-auth php packages to latest develop versions
- update npm packages to latest versions
- update public/.htaccess

closes #6

- add installGateway to app config
- update route names and groups
- remove `author_name` and `author_email` from `episodes` table
- remove `author_name` and `author_email` from `podcasts` table
- remove `owner_id` + add `created_by` and `updated_by` fields in `podcasts` and `episodes` tables
- remove unnecessary comments in database fields
- remove confirm password inputs from auth forms for better ux
- rename `pub_date` field to `published_at` and add publication time field in episode form

closes #14, #28

- add .editorconfig file
- format all files to comply with castopod's coding style
- switch parsedown dependency with commonmark library to better follow commonmark spec for markdown
- add prettier command to format all project files at once

closes #16

- bundle js using parcel
- add markdown editor, html editor, dropdown and tooltip features using third-party packages
- integrate optimized inline svg icons from RemixIcon using svgo and a php helper
- add scripts in package.json to bundle icons, images, css and js
- update tailwind config to add purgecss lookups and typography plugin
- refactor views to add missing pages in user journey
- update admin's holy grail layout using css grid

- add AuthSeeder to bootstrap authorization data and remove UserSeeder
- create a superadmin group having all authorizations
- refactor routes and controller methods to separate get and post requests
- refactor admin views with a title section in layout
- add contributors section to podcasts to manage contributions (add, edit roles and remove)

closes #3, #18

- overwrite myth/auth config with castopod app needs
- create custom views for users authentication
- add admin area bootstrapped by admin controller
- shift podcast and episodes crud to admin area
- reorganize view layouts
- update docs for database migration
- add myth-auth to DEPENDENCIES.md

closes #11

- refactor model / entity and controller logic for DRY code
- update episodes and podcasts
migrations
- define callbacks for podcast and episode models for enclosure update and cache
clearing

- refactor episode, podcast and category entities to add dynamic properties
- refactor Routes when adding feed route
- update migration files to better fit itunes' and rss' specs
- update podcast and episode forms
- add SimpleRSSElement class to Libraries
- add rss_helper
- update home controller to redirect if system has only one podcast