Feature/cli build index

[steph-ben]

This cli will help generating cfgrib indexes in particular directories, allowing to :

• separate indexing process in particular task
• speedup first GRIB opening in python

Example of usage :

$ cfgrib build_index --help
Usage: cfgrib build_index [OPTIONS] INPATHS...

Options:
  --index-basedir TEXT
  --force-index-creation TEXT
  --help                       Show this message and exit.

$ cfgrib build_index --index-basedir /tmp/indexes nam.t00z.awp21100.tm00.grib2
nam.t00z.awp21100.tm00.grib2: Creating index
$ ls -lh /tmp/indexes/nam.t00z.awp21100.tm00.grib2.idx 
-rwxr-xr-x 1 steph steph 13K Dec  4 18:01 /tmp/indexes/nam.t00z.awp21100.tm00.grib2.idx

[FussyDuck]

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1 out of 2 committers have signed the CLA.

✅ steph-ben
❌ benchimols
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