Improvements to the installation script

[sarog]

This first PR is part of a series of changes to refactor the installation script. It maintains its original functionality and does not break or go against the current method of installing TRMM.

Some of the changes in this PR include:

1. Standardize variable names and abstract them as much as possible.
2. Modularize script logic & flow by creating functions to eliminate duplicate code.
3. Apply a consistent formatting style.
4. Log installation to a file for troubleshooting purposes. ✅
5. Eliminate the requirement of adding the tacticalrmm user to sudo. ✅

The long-term goals for modernizing the script are as follows:

1. Improve code readability and allow some customization by the sysadmin.
2. Allow automated installs for quick deployments (e.g. ./install.sh -args).
3. Eliminate useless third-party dependencies, such as lsb-release.
4. Branch out configuration files into separate files.
5. Make the scripts portable so TRMM can be used on other operating systems besides Linux (and avoid bashism).

[codecov[bot]]

Codecov Report

Merging #1176 (06d9fa2) into develop (7ac9af1) will not change coverage. The diff coverage is n/a.

:exclamation: Current head 06d9fa2 differs from pull request most recent head 091aedc. Consider uploading reports for the commit 091aedc to get more accurate results

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[silversword411]

There's already a previous PR in the works for major modifications to the install script.

Working on the same install.sh in different directions is going to have one path have to re-write/fix. Might want to see about collaboration working together on this...or the devs will have to pick a winner in the end

[sarog]

I'm aware of the previous contribution and open to collaborate, although our long-term goals are conflicting from the looks of it. I'm working to slim down the installer and make it portable without having to rely on additional components or dependencies. This means avoiding dialogs and keeping it simple. In my opinion, the installer is a one-time script to deploy TRMM, not a Swiss Army knife to manage the instance.

I prefer the project's lead developers choose what matters to them. It's also understandable if they do not wish to accept any contributions to the installer or related scripts at this time.

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