fix: #41

fix(install): edit host_url helper and remove back() when create .env

- add `.env.example` and `INSTALL.md` to castopod bundle for installation docs
- update seeders to be silent on insert errors
- update install layout
- add manual config instructions when .env file is not writable
- fix eslint error in Charts.ts module

closes #32

- 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 .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

- 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

- add $mediaRoot parameter in app config
- add and refactor helpers : id3, media and url
- add basic vscode settings for code formatting in devcontainer.json
- set post_max_size to Dockerfile