Handle long secondary index names

As per Couchbase documentation, there is no limit on the length of secondary index names. Below is the snippet on index names:

https://docs.couchbase.com/server/current/n1ql/n1ql-language-reference/createindex.html#:~:text=Valid%20GSI%20index%20names%20can,set%20for%20an%20index%20name.

"Valid GSI index names can contain any of the following characters: A-Z a-z 0-9 # _, and must start with a letter, [{{A-Z}} {{a-z}}]. The minimum length of an index name is 1 character and there is no maximum length set for an index name."

Many operating systems impose a limit on the length of file names. The file name for the index on disk will be of the form <bucket_name><index_name><inst_id>_<partn_id>. Bucket name is limited to 100 characters. If the index name exceeds a certain limit, creation of index would fail.