Dev login activity

[aleexgheorghe]

Hello team,

This pull request brings some basic news regarding the design of the login & register activities.

• [x] Created the necessary classes for the development of this functionality.
• [x] Implemented the necessary methods in the register class to avoid user errors.
• [x] Implemented the new application branding (logo).
• [x] Implemented the activities with their corresponding design.
• [x] Updated the strings.xml file implementing all the texts.
• [x] Modified the Manifest to change the default activity to login.

Login	Register

Any suggestions before accepting it are welcome! Thank you very much.

[aleexgheorghe]

Hello again!

I have made all the changes so that there is no compatibility problem, I apologize for my despite with the camelcase.

Also, I have implemented a useful class to check if the data entered by the user is correct to avoid absurd queries to the database or mitigation of a massive query attack.

Please, if any other changes are needed do not hesitate to let me know. Thank you!