Update /captain page

[kmcurry]

Remove "Click to Apply" and change the text below it to:

Our inaugural class of the Brigade Captains program is currently underway. Classes are annual. The current class will run from September 1 to August 31. Future classes may start bi-annually. Don't wait until the next class of Brigade Captain to get started as a leader and organizer for Brigade in your city! Email the Brigade Support Team and let us know that your interested [MAILTO LINK, ?subject=I want to lead and organize in...]. Create a Brigade Meetup [LINK], invite your friends and hold your first meeting to choose an activity [LINK].