Rework README.md file and remove outdated content

[NicolasFussberger]

The current Readme file content was introduced with the initial contribution and its content was quite outdated.

Closes: #257

[github-actions]

License Check Results

🚀 The license check job ran with the Bazel command:

bazel run --lockfile_mode=error //:license-check

Status: ⚠️ Needs Review

Click to expand output

[License Check Output]
Extracting Bazel installation...
Starting local Bazel server (8.4.2) and connecting to it...
INFO: Invocation ID: bdcad05d-ceff-4f8c-99ab-1ba6df97076b
Computing main repo mapping: 
Computing main repo mapping: 
Loading: 
Loading: 0 packages loaded
Loading: 0 packages loaded
Loading: 0 packages loaded
    currently loading: 
Loading: 0 packages loaded
    currently loading: 
Loading: 0 packages loaded
    currently loading: 
Analyzing: target //:license-check (1 packages loaded, 0 targets configured)
Analyzing: target //:license-check (1 packages loaded, 0 targets configured)

Analyzing: target //:license-check (30 packages loaded, 10 targets configured)

Analyzing: target //:license-check (85 packages loaded, 10 targets configured)

Analyzing: target //:license-check (86 packages loaded, 10 targets configured)

Analyzing: target //:license-check (135 packages loaded, 2408 targets configured)

Analyzing: target //:license-check (146 packages loaded, 5388 targets configured)

Analyzing: target //:license-check (147 packages loaded, 7444 targets configured)

Analyzing: target //:license-check (153 packages loaded, 8081 targets configured)

Analyzing: target //:license-check (158 packages loaded, 8130 targets configured)

Analyzing: target //:license-check (158 packages loaded, 8130 targets configured)

Analyzing: target //:license-check (158 packages loaded, 8130 targets configured)

Analyzing: target //:license-check (162 packages loaded, 10142 targets configured)

Analyzing: target //:license-check (162 packages loaded, 10142 targets configured)

INFO: Analyzed target //:license-check (163 packages loaded, 10268 targets configured).
[13 / 16] JavaToolchainCompileClasses external/rules_java+/toolchains/platformclasspath_classes; 0s disk-cache, processwrapper-sandbox
[15 / 16] [Prepa] Building license.check.license_check.jar ()
INFO: Found 1 target...
Target //:license.check.license_check up-to-date:
  bazel-bin/license.check.license_check
  bazel-bin/license.check.license_check.jar
INFO: Elapsed time: 26.050s, Critical Path: 2.47s
INFO: 16 processes: 12 internal, 3 processwrapper-sandbox, 1 worker.
INFO: Build completed successfully, 16 total actions
INFO: Running command line: bazel-bin/license.check.license_check ./formatted.txt <args omitted>
usage: org.eclipse.dash.licenses.cli.Main [-batch <int>] [-cd <url>]
       [-confidence <int>] [-ef <url>] [-excludeSources <sources>] [-help] [-lic
       <url>] [-project <shortname>] [-repo <url>] [-review] [-summary <file>]
       [-timeout <seconds>] [-token <token>]

[github-actions]

The created documentation from the pull request is available at: docu-html

[SimonKozik]

Thanks for providing this much needed refresh.