Refactor ORF main type, update entire writting API and other general changes

[camilogarciabotero]

This PR creates important changes to the API including:

• A more stable ORF type that asserts for incorrect ORFs.
• Extended Base.getindex method to better handle ORF enabling: seq[orf] regardless of the ORF strand.
• The write_* API is much more stable and its been rewriten to handle IOStreams and IOBuffers as well.
• The new record_orfs_fna and record_orfs_faa methods intearact with the FASTX interface.
• Codebase has been reduced. Direct String manipulation is not enabled for findorfs and get_* methods.
• Docstrings have been updated following method updates.
• Better tests and now Aqua.jl is used for several tests as well.

Still some things to do:

• Create a new documentation section to describe write_orfs* API
• Update CHANGELOG.md using the bulletpoints of this PR.
• Update Project.toml to bump version.
• Add the Aqua badge.