I need a some application software for LEDE, but I don't have required experience. It is possible to create a "bourse" for this requests?
I think you could request just here initially. Most of us are running LEDE on a consumer grade router, so resources are limited. Even if you could add space via e.g a USB port, processing power and RAM are limited.
What application(s) are you missing? There are already a lot of packages availlable. Or people have created some script to handle special tasks.
I need a Web Map Server 
I never saw a map server, so I looked into this. I don't think out garden variety routers are powerful enough. What system/device are you thinking of running this?
Running a web server, a MySQL database, the map server plus all resources (the real maps). It could be done given enough processing power and storage. Not sure how responsive and multi user...
This question about usage devices, widest than simple router.
I use "car" we826-based device as Internet access point and multipurpose server on my sailboat. Device has a SD slot, usb jack and low power consumption. It has enough performance capabilities for me.