Make it a real library (#102)

* Moved files to module

Signed-off-by: Arnau Mora Gras <arnyminerz@proton.me>

* Configured modules

Signed-off-by: Arnau Mora Gras <arnyminerz@proton.me>

* Fixed paths

Signed-off-by: Arnau Mora Gras <arnyminerz@proton.me>

* Configured Jitpack

Signed-off-by: Arnau Mora Gras <arnyminerz@proton.me>

* Updated usage instructions

Signed-off-by: Arnau Mora Gras <arnyminerz@proton.me>

* Config for `maven-publish`

Signed-off-by: Arnau Mora Gras <arnyminerz@proton.me>

* typo

Signed-off-by: Arnau Mora <arnyminerz@proton.me>

* Deprecations

Signed-off-by: Arnau Mora <arnyminerz@proton.me>

* Using environment variable for version

Signed-off-by: Arnau Mora <arnyminerz@proton.me>

* Excluded `META-INF/INDEX.LIST`

Signed-off-by: Arnau Mora <arnyminerz@proton.me>

* Included `META-INF/INDEX.LIST` again

Signed-off-by: Arnau Mora <arnyminerz@proton.me>

* Excluded dateutils

Signed-off-by: Arnau Mora <arnyminerz@proton.me>

* Excluded all groovy trans. dependencies

Signed-off-by: Arnau Mora <arnyminerz@proton.me>

* Excluded groovy with configurations

Signed-off-by: Arnau Mora <arnyminerz@proton.me>

* Removed transitive dependencies

Signed-off-by: Arnau Mora <arnyminerz@proton.me>

* Minor changes, rename source directories from java to kotlin

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Signed-off-by: Arnau Mora Gras <arnyminerz@proton.me>
Signed-off-by: Arnau Mora <arnyminerz@proton.me>
Co-authored-by: Ricki Hirner <hirner@bitfire.at>