DietPi-Software | Reinstalls: Better handle existing configs and install dirs

[MichaIng]

Status: Ready

• Check further install titles
  • Enough for now, this is a larger task, most properly over the next multiple releases.

Testing
🈯️ Jackett + reinstall
🈯️ RoonServer + reinstall
🈯️ MariaDB, SQLite and Redis after PHP
🈯️ phpBB + reinstall

[ INFO ] DietPi-Software | Forums install dir "/var/www/phpBB3" already exists. Download and install steps will be skipped.
 - Please manually backup your config files+data, remove the install dir and rerun "dietpi-software (re)install 54" if you need to reinstall.
 - If you want to update the Forums instance, please follow the instructions from WebUI ACP.
...
[ INFO ] DietPi-Create_MySQL_DB | "phpbb3" MariaDB database already exists. Aborting...

Reference:

• https://github.com/Fourdee/DietPi/issues/2212
• https://github.com/Fourdee/DietPi/issues/2187

Commit list/description:

• DietPi-Software | Jackett: Fix reinstall in case of existent install dir
• DietPi-Software | RoonServer: Skip download and install, if already install dir already exist; Rely on internal auto updater
• DietPi-Software | Minor coding
• DietPi-Software | Assure that required database PHP modules are installed as well, if PHP was already installed before
• DietPi-Software | phpBB: Install v3.2.3, use bzip2 archive => lower download size
• DietPi-Software | phpBB: Skip Download_Install, if install already exists. Ask user for manual config/data/plugin backup and install dir removal, if reinstall required; Updates should be applied via internal update package method.
• DietPi-Create_MySQL_DB | Skip database creation, if already existent. Creation anyway fails otherwise.
• DietPi-Software | Plex/Transmission: Prevent doubled service file entries on reinstall

[MichaIng]

My goodness, Mono is quite monster. "Quick" testing of the installs impossible. Looooong Mono install, looong compiling, loooong loading of software run by Mono... Reminds of of Java, although way better in terms of RAM usage 😉.

[MichaIng]

@Fourdee
Ready to merge from my point of view. Fixes some issues with last dietpi-software change and reported software reinstalls (wrong unpack target when existent).

I will go on checking other software installs, but will do this in steps.

We have doubled webserver + PHP install fix, but does not harm, my second step will just be ignored due to =1 already the case. Will rework dependencies to have a merged consistent method.

[Fourdee]

@MichaIng

Looks good, great work 👍 Will merge.