infra: make build auto reload changes

[kevinjqliu]

When running make build, this will automatically refresh any changes made locally. Previously, we had to stop and restart the container.

This is done by using the --autoreload from pelican and keeping it running as a background process (in docker)
Also updated the README.
This only affects local preview, we do not use make build when deploying the site

Here's the pelican options (took me a while to find)

uvx pelican --help

usage: pelican [-h] [-t THEME] [-o OUTPUT] [-s SETTINGS] [-d] [-v] [-q] [-D] [--version] [-r]
               [--print-settings [SETTING_NAME ...]] [--relative-urls] [--cache-path CACHE_PATH]
               [--ignore-cache] [--fatal errors|warnings] [--log-handler {plain,rich}]
               [--logs-dedup-min-level {DEBUG,INFO,WARNING,ERROR}] [-l] [-p PORT] [-b BIND]
               [-e [OVERRIDES ...]]
               [path]

A tool to generate a static blog, with restructured text input files.

positional arguments:
  path                  Path where to find the content files. (default: None)

options:
  -h, --help            show this help message and exit
  -t, --theme-path THEME
                        Path where to find the theme templates. If not specified, it will use the default
                        one included with pelican. (default: None)
  -o, --output OUTPUT   Where to output the generated files. If not specified, a directory will be created,
                        named "output" in the current path. (default: None)
  -s, --settings SETTINGS
                        The settings of the application, this is automatically set to pelicanconf.py if a
                        file exists with this name. (default: None)
  -d, --delete-output-directory
                        Delete the output directory. (default: None)
  -v, --verbose         Show all messages. (default: None)
  -q, --quiet           Show only critical errors. (default: None)
  -D, --debug           Show all messages, including debug messages. (default: None)
  --version             Print the pelican version and exit.
  -r, --autoreload      Relaunch pelican each time a modification occurs on the content files. (default:
                        False)
  --print-settings [SETTING_NAME ...]
                        Print current configuration settings and exit. Append one or more setting name
                        arguments to see the values for specific settings only. (default: None)
  --relative-urls       Use relative urls in output, useful for site development (default: False)
  --cache-path CACHE_PATH
                        Directory in which to store cache files. If not specified, defaults to "cache".
                        (default: None)
  --ignore-cache        Ignore content cache from previous runs by not loading cache files. (default:
                        False)
  --fatal errors|warnings
                        Exit the program with non-zero status if any errors/warnings encountered. (default:
                        )
  --log-handler {plain,rich}
                        Which handler to use to format log messages. The `rich` handler prints output in
                        columns. (default: rich)
  --logs-dedup-min-level {DEBUG,INFO,WARNING,ERROR}
                        Only enable log de-duplication for levels equal to or above the specified value
                        (default: WARNING)
  -l, --listen          Serve content files via HTTP and port 8000. (default: False)
  -p, --port PORT       Port to serve HTTP files at. (default: 8000) (default: None)
  -b, --bind BIND       IP to bind to when serving files via HTTP (default: 127.0.0.1) (default: None)
  -e, --extra-settings [OVERRIDES ...]
                        Specify one or more SETTING=VALUE pairs to override settings. VALUE must be in JSON
                        notation: specify string values as SETTING='"some string"'; booleans as
                        SETTING=true or SETTING=false; None as SETTING=null. (default: {}

[kevinjqliu]

cc @alamb whenever you have a chance, could you take a look.
this has been a annoyance for me to always restart the container 😄 finally fixed

[alamb]

Thank you @kevinjqliu -- I have also been annoyed about this.

I tried the PR out locally and it works great!