[Mobile] Categories screen have been created

[bbenginbestas]

Description:

• Initial design of categories page was made.

Tasks Done:

• [x] A new screen was created.
• [x] Initial design of the page was made.

Reviewer: @kardelendemiral

Notes:

• For the API section of the page, I asked Burak for help. He will do some important sections of the screen, including API calls.

Issue:

• See #460

[kardelendemiral]

The category page seems ok. Users now can easily access the categories from there. Thank you for the effort! I am merging this PR.