Dockerfile for Uguu #71

This commit adds the directory /docker, holding a Dockerfile and its supporting files to build an image and spin up a docker container of the latest release with SQLite as a DB

* docker-entrypoint.sh: daemonize both PHP and Nginx and performs
config substitutions on dist.json

* uguu.conf: The Nginx template to serve uguu

* dist.json: Variablized values for substitution by entrypoint script

* .env: The environment variables for the user to configure

* Makefile: Modify to include targets for building, creating, and
purging images/containers

If this PR is approved, It'd be instructional to update the Uguu docs of these below make commands that I added for each of the docker targets that went inside the Makefile.

export UGUU_RELEASE_VER="1.5.2"
export DOCKER_TAG="v1.5.2"
export CONTAINER_NAME=uguu

(or)

make UGUU_RELEASE_VER="1.5.2" DOCKER_TAG="v1.5.2" build-image
make DOCKER_TAG=v1.5.2 CONTAINER_NAME=uguu run-container
make DOCKER_TAG=v1.5.2 CONTAINER_NAME=uguu purge-container

Kudos, SonarCloud Quality Gate passed!

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
0.0% Duplication

Kudos, SonarCloud Quality Gate passed!    [![Quality Gate passed](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/checks/QualityGateBadge/passed-16px.png 'Quality Gate passed')](https://sonarcloud.io/dashboard?id=nokonoko_Uguu&pullRequest=71) [![Bug](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/common/bug-16px.png 'Bug')](https://sonarcloud.io/project/issues?id=nokonoko_Uguu&pullRequest=71&resolved=false&types=BUG) [![A](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/checks/RatingBadge/A-16px.png 'A')](https://sonarcloud.io/project/issues?id=nokonoko_Uguu&pullRequest=71&resolved=false&types=BUG) [0 Bugs](https://sonarcloud.io/project/issues?id=nokonoko_Uguu&pullRequest=71&resolved=false&types=BUG) [![Vulnerability](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/common/vulnerability-16px.png 'Vulnerability')](https://sonarcloud.io/project/issues?id=nokonoko_Uguu&pullRequest=71&resolved=false&types=VULNERABILITY) [![A](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/checks/RatingBadge/A-16px.png 'A')](https://sonarcloud.io/project/issues?id=nokonoko_Uguu&pullRequest=71&resolved=false&types=VULNERABILITY) [0 Vulnerabilities](https://sonarcloud.io/project/issues?id=nokonoko_Uguu&pullRequest=71&resolved=false&types=VULNERABILITY) [![Security Hotspot](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/common/security_hotspot-16px.png 'Security Hotspot')](https://sonarcloud.io/project/security_hotspots?id=nokonoko_Uguu&pullRequest=71&resolved=false&types=SECURITY_HOTSPOT) [![A](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/checks/RatingBadge/A-16px.png 'A')](https://sonarcloud.io/project/security_hotspots?id=nokonoko_Uguu&pullRequest=71&resolved=false&types=SECURITY_HOTSPOT) [0 Security Hotspots](https://sonarcloud.io/project/security_hotspots?id=nokonoko_Uguu&pullRequest=71&resolved=false&types=SECURITY_HOTSPOT) [![Code Smell](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/common/code_smell-16px.png 'Code Smell')](https://sonarcloud.io/project/issues?id=nokonoko_Uguu&pullRequest=71&resolved=false&types=CODE_SMELL) [![A](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/checks/RatingBadge/A-16px.png 'A')](https://sonarcloud.io/project/issues?id=nokonoko_Uguu&pullRequest=71&resolved=false&types=CODE_SMELL) [0 Code Smells](https://sonarcloud.io/project/issues?id=nokonoko_Uguu&pullRequest=71&resolved=false&types=CODE_SMELL) [![No Coverage information](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/checks/CoverageChart/NoCoverageInfo-16px.png 'No Coverage information')](https://sonarcloud.io/component_measures?id=nokonoko_Uguu&pullRequest=71) No Coverage information [![0.0%](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/checks/Duplications/3-16px.png '0.0%')](https://sonarcloud.io/component_measures?id=nokonoko_Uguu&pullRequest=71&metric=new_duplicated_lines_density&view=list) [0.0% Duplication](https://sonarcloud.io/component_measures?id=nokonoko_Uguu&pullRequest=71&metric=new_duplicated_lines_density&view=list)

I'll add the documentation soon.

Instead of Ubuntu it's now using Alpine since it's lighter and much faster, also changed a bunch of configuration and scripts.