Add header in each defense system pages

content/2.defense-systems/abi2.md

-# Abi2
-
-## Example of genomic structure
+---
+title: Abi2
+---
 
 The Abi2 system is composed of one protein: Abi\_2.
 

content/2.defense-systems/abia.md

-# AbiA
-
-## Example of genomic structure
+---
+title: AbiA
+---
 
 The AbiA system have been describe in a total of 2 subsystems.
 

content/2.defense-systems/abib.md

-# AbiB
-
-## Example of genomic structure
+---
+title: AbiB
+---
 
 The AbiB system is composed of one protein: AbiB.
 

content/2.defense-systems/abic.md

-# AbiC
-
-## Example of genomic structure
+---
+title: AbiC
+---
 
 The AbiC system is composed of one protein: AbiC.
 

content/2.defense-systems/abid.md

-# AbiD
-
-## Example of genomic structure
+---
+title: AbiD
+---
 
 The AbiD system is composed of one protein: AbiD.
 

content/2.defense-systems/abie.md

-# AbiE
-
-## Description
+---
+title: AbiE
+---
 
 AbiE is a family of an anti-phage defense systems. They act through a Toxin-Antitoxin mechanism, and are comprised of a pair of genes, with one gene being toxic while the other confers immunity to this toxicity. 
 

content/2.defense-systems/abig.md

-# AbiG
-
-## Example of genomic structure
+---
+title: AbiG
+---
 
 The AbiG system is composed of 2 proteins: AbiGi and, AbiGii.
 

content/2.defense-systems/abih.md

-# AbiH
+---
+title: AbiH
+---
 
 ## Example of genomic structure
 

content/2.defense-systems/abii.md

-# AbiI
+---
+title: AbiI
+---
 
 ## Example of genomic structure
 

content/2.defense-systems/abij.md

-# AbiJ
+---
+title: AbiJ
+---
 
 ## Example of genomic structure
 

content/2.defense-systems/abik.md

-# AbiK
+---
+title: AbiK
+---
 
 ## Example of genomic structure
 

content/2.defense-systems/abil.md

-# AbiL
+---
+title: AbiL
+---
 
 ## Example of genomic structure
 

content/2.defense-systems/abin.md

-# AbiN
+---
+title: AbiN
+---
 
 ## Example of genomic structure
 

content/2.defense-systems/abio.md

-# AbiO
+---
+title: AbiO
+---
 
 ## Example of genomic structure
 

content/2.defense-systems/abip2.md

-# AbiP2
+---
+title: AbiP2
+---
 
 ## Example of genomic structure
 

content/2.defense-systems/abiq.md

-# AbiQ
+---
+title: AbiQ
+---
 
 ## Example of genomic structure
 

content/2.defense-systems/abir.md

-# AbiR
+---
+title: AbiR
+---
 
 ## Example of genomic structure
 

content/2.defense-systems/abit.md

-# AbiT
+---
+title: AbiT
+---
 
 ## Example of genomic structure
 

content/2.defense-systems/abiu.md

-# AbiU
+---
+title: AbiU
+---
 
 ## Example of genomic structure
 

content/2.defense-systems/abiv.md

-# AbiV
+---
+title: AbiV
+---
 
 ## Example of genomic structure