Add project command to suggest coding project ideas

[mbn-code]

This pull request introduces a new command to the bot for providing coding project ideas. The most important changes include adding the projectCommand function, updating the command list, and adding new project ideas and coding questions to the respective resource files.

New command addition:

• src/commands/project_cmd.cpp: Implemented the projectCommand function to reply with a coding project idea.
• src/commands/commands.h: Added the declaration for the projectCommand function.
• src/main.cpp: Updated the command list to include the new projectCommand.

Resource file updates:

• src/res/project.txt: Added a list of new project ideas.
• src/res/coding.txt: Added new coding questions.

Build configuration:

• CMakeLists.txt: Included the new project_cmd.cpp file in the build configuration.

[ebcq]

LGTM now, thanks!