Add BLAST to UI

[krupalip]

• [ ] add text box (sequence to search) and button for BLAST under taxonomy box.
• [ ] enable text box only if Amplicon is provided in the search form.

[krupalip]

• [x] add text area for sequence user input
• [x] make text area conditional (enable only if amplicon is selected)
• [x] add 'Run blast' button
• [x] make button conditional (enable only if sequence is provided in text area)
• [x] attach api call to button

[krupalip]

• [x] disable 'run blast' button if query is already submitted and enable processed
• [x] add spinner if blast is in progress
• [x] display file download link
• [x] display alert blast is in progress

[krupalip]

PR submitted