Modify hostname check to not fail on over 26 chars.

[swirtSJW]

The current regex pattern causes an incorrect identification of invalid hostnames as anything longer than 26 characters which is not correct. Handling of this is shifted from regex to a core php function to validate hostnames.

[swirtSJW]

Test cases
// good 62
Passes "s3://pdc-111112222233333444445555566666-s3-dfc-data-extra-long-name/DFC_FACILITY.csv";

//good 63
Passes "s3://pdc-1111122222333334444455555666667-s3-dfc-data-extra-long-name/DFC_FACILITY.csv";

// bad 64
Invalid "s3://pdc-11111222223333344444555556666677-s3-dfc-data-extra-long-name/DFC_FACILITY.csv";

// bad 65
Invalid "s3://pdc-111112222233333444445555566666777-s3-dfc-data-extra-long-name/DFC_FACILITY.csv";

//bad 99
Invalid"s3://pdc-11111222223333344444555556666677777888889999900000abcdefcgijklmnopq-s3-dfc-data-extra-long-name/DFC_FACILITY.csv";