CI: add checkstyle rule for RedundantModifier

[algattik]

What this PR changes/adds

Add a rule for checkstyle check RedundantModifier.
Checks for redundant modifiers, such as usage of public and abstract for method declarations in interfaces, or public constructor in private static classes.

Why it does that

Improve code consistency and reduce spurious PR diffs.

Further notes

Linked Issue(s)

Relates to #991

Checklist

• added appropriate tests?
• performed checkstyle check locally?
• added/updated copyright headers?
• documented public classes/methods?
• added/updated relevant documentation?
• added relevant details to the changelog? (skip with label no-changelog)
• formatted title correctly? (take a look at the CONTRIBUTING and styleguide for details)

[codecov-commenter]

Codecov Report

Merging #1166 (38ea08b) into main (79b58b8) will decrease coverage by 0.00%.
The diff coverage is 88.88%.

@@             Coverage Diff              @@
##               main    #1166      +/-   ##
============================================
- Coverage     58.45%   58.44%   -0.01%     
+ Complexity     2726     2725       -1     
============================================
  Files           698      698              
  Lines         15464    15464              
  Branches       1047     1047              
============================================
- Hits           9039     9038       -1     
  Misses         6002     6002              
- Partials        423      424       +1     

Impacted Files	Coverage Δ
...taspaceconnector/boot/monitor/MonitorProvider.java	0.00% <0.00%> (ø)
...description/AbstractDescriptionRequestHandler.java	51.35% <ø> (ø)
.../control/HttpApiKeyAuthContainerRequestFilter.java	81.25% <ø> (ø)
...aspaceconnector/aws/dataplane/s3/S3DataSource.java	50.00% <0.00%> (ø)
...ceconnector/core/base/policy/PolicyEngineImpl.java	81.35% <100.00%> (ø)
...ids/core/transform/IdsTransformerRegistryImpl.java	65.21% <100.00%> (ø)
...connector/api/auth/BasicAuthenticationService.java	97.05% <100.00%> (ø)
...aceconnector/azure/cosmos/dialect/LimitClause.java	100.00% <100.00%> (ø)
...ceconnector/azure/cosmos/dialect/OffsetClause.java	100.00% <100.00%> (ø)
...econnector/azure/cosmos/dialect/OrderByClause.java	81.81% <100.00%> (ø)
... and 9 more

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