Make team dynamics robust

[lordshashank]

Currently a builder can only signup in one team through initializeTeam function and can't change the team.

Implement a changeTeam function along with making required changes in other functions that enable builders to change team after registering in one.
ALso implement the following checks-

• NotInTeam modifier
• UniqueTeamName modifier

[yomanthunder]

Re-impliment initializeTeam

Issues with Present initializeTeam Function:

• The person initializing the team has way too much power as they can add other builders without their consent.
• There isn't a function to change teams.

Proposed Solution:

• The person initializing the team will create a team with only themselves in it.
• We generate a unique code for each team created (which can only be accessed by team members).
• People can join a team based on the team code.

This process makes the code less complicated and easily customizable for people who want to join, leave, or change teams based on their own consent.
I will make the pr today after your conformation @lordshashank

[lordshashank]

Team code would not work, everything is publicly accessible in blockchain. Just implement changeTeam function compatible with code. we would have to block team changing after some time into the hackathon so as to avoid malicious behaviour