Make _flower series of decompilers coexist

[meiMingle]

As the title says, this is to implement #866. This PR refers to the method in class-file-indexer to relocate the package path of the _flower series decompiler to achieve the purpose of coexistence without interfering with each other.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 79.13043% with 96 lines in your changes missing coverage. Please review.

Project coverage is 64.91%. Comparing base (e6b5b7f) to head (5dc5478).

Files with missing lines	Patch %	Lines
...ces/decompile/fernflower/FernflowerDecompiler.java	18.18%	18 Missing :warning:
...vices/decompile/forgeflower/ForgeflowerConfig.java	85.08%	16 Missing and 1 partial :warning:
...s/decompile/forgeflower/ForgeflowerDecompiler.java	19.04%	17 Missing :warning:
...ervices/decompile/fernflower/FernflowerConfig.java	86.11%	14 Missing and 1 partial :warning:
...ervices/decompile/vineflower/VineflowerConfig.java	94.15%	9 Missing :warning:
...ervices/decompile/fernflower/FernflowerLogger.java	33.33%	8 Missing :warning:
...vices/decompile/forgeflower/ForgeflowerLogger.java	33.33%	8 Missing :warning:
...ces/decompile/vineflower/VineflowerDecompiler.java	76.47%	3 Missing and 1 partial :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #871 +/- ## ============================================ + Coverage 64.54% 64.91% +0.37% - Complexity 2984 2994 +10 ============================================ Files 368 374 +6 Lines 15610 15892 +282 Branches 2138 2160 +22 ============================================ + Hits 10076 10317 +241 - Misses 4493 4529 +36 - Partials 1041 1046 +5 ```

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