[fix] utils/lib.sh: various typos in messages and comments

source_dot_config() {

    if [[ ! -e "${DOT_CONFIG}" ]]; then

        err_msg "configuration does not extsts at: ${DOT_CONFIG}"

        err_msg "configuration does not exists at: ${DOT_CONFIG}"

        return 42

    fi

    # shellcheck disable=SC1090

}

wait_key(){

    # usage: waitKEY [<timeout in sec>]

    # usage: wait_key [<timeout in sec>]

    clean_stdin

    local _t=$1

    NGINX_DEFAULT_SERVER=/etc/nginx/nginx.conf

    # Including *location* directives from a dedicated config-folder into the

    # server directive is, what what fedora and centos (already) does.

    # server directive is, what fedora and centos (already) does.

    NGINX_APPS_ENABLED="/etc/nginx/default.d"

    # We add a apps-available folder and linking configurations into the

nginx_install_app() {

    # usage:  nginx_install_app [<template option> ...] <myapp>

    # usage:  nginx_install_app [<template option> ...] <myapp.conf>

    #

    # <template option>:   see install_template